food
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inge ...
produced by the
mammary gland
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primat ...
s of
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s. It is the primary source of
nutrition
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficient n ...
for young mammals (including
breastfed
Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
human infants) before they are able to digest solid food. Immune factors and immune-modulating components in milk contribute to
milk immunity Milk immunity is the protection provided to immune system of an infant via the biologically active components in milk, typically provided by the infant's mother.
Mammalian milk
All mammalian milk contains water, sugar, fat, vitamins, and protein ...
. Early-
lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...
milk, which is called
colostrum
Colostrum, also known as beestings or first milk, is the first form of milk produced by the mammary glands of mammals (including humans) immediately following delivery of the newborn. Colostrum powder is rich in high protein and low in sugar and ...
, contains
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
that strengthen the
immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
, and thus reduces the risk of many diseases. Milk contains many nutrients, including
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
and
lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix '' - ...
.
As an agricultural product,
dairy
A dairy is a business enterprise established for the harvesting or processing (or both) of animal milk – mostly from cows or buffaloes, but also from goats, sheep, horses, or camels – for human consumption. A dairy is typically located on ...
dairy farms
A dairy is a business enterprise established for the harvesting or processing (or both) of animal milk – mostly from cows or buffaloes, but also from goats, sheep, horses, or camels – for human consumption. A dairy is typically located on ...
produced around of milk from 260 million dairy cows.
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
is the world's largest producer of milk and the leading exporter of
skimmed milk
Skimmed milk (British English), or skim milk (American English), is made when all the milkfat is removed from whole milk. It tends to contain around 0.1% fat.
Background
Historically, skimmed milk was used for fattening pigs, and was recommende ...
powder, but it exports few other milk products. Because there is an ever-increasing demand for dairy products within India, it could eventually become a net importer of dairy products. New Zealand, Germany and the Netherlands are the largest exporters of milk products. The
US CDC
The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency, under the United S ...
recommends that children over the age of 12 months should have two servings of dairy milk products a day.
More than six billion people worldwide consume milk and milk products, and between 750 and 900 million people live in dairy-farming households.
Etymology and terminology
The term ''milk'' comes from "Old English ''meoluc'' (West Saxon), ''milc'' (Anglian), from Proto-Germanic *''meluks'' "milk" (source also of Old Norse ''mjolk'', Old Frisian ''melok'', Old Saxon ''miluk'', Dutch ''melk'', Old High German ''miluh'', German ''Milch'', Gothic ''miluks'')".
In food use, from 1961, the term ''milk'' has been defined under
Codex Alimentarius
The Codex Alimentarius () is a collection of internationally recognized standards, codes of practice, guidelines, and other recommendations published by the Food and Agriculture Organization of the United Nations relating to food, food production ...
standards as: "the normal mammary secretion of milking animals obtained from one or more milkings without either addition to it or extraction from it, intended for consumption as liquid milk or for further processing." The term ''dairy'' relates to animal milk and animal milk production.
Types of consumption
There are two distinct categories of milk consumption: all infant mammals drink milk directly from their mothers’ bodies, and it is their primary source of nutrition; and humans obtain milk from other mammals for consumption by humans of all ages, as one component of a varied diet.
Nutrition for infant mammals
In almost all mammals, milk is fed to
infant
An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
s through
breastfeeding
Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...
, either directly or by expressing the milk to be stored and consumed later. The early milk from mammals is called
colostrum
Colostrum, also known as beestings or first milk, is the first form of milk produced by the mammary glands of mammals (including humans) immediately following delivery of the newborn. Colostrum powder is rich in high protein and low in sugar and ...
. Colostrum contains
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
that provide protection to the newborn baby as well as nutrients and growth factors. The makeup of the colostrum and the period of secretion varies from species to species.
For humans, the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
recommends exclusive breastfeeding for six months and breastfeeding in addition to other food for up to two years of age or more. In some cultures it is common to breastfeed children for three to five years, and the period may be longer.
Fresh goats' milk is sometimes substituted for
breast milk
Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by mammary glands located in the breast of a human female. Breast milk is the primary source of nutrition for newborns, containing fat, protein, carbohydrates ( lacto ...
, which introduces the risk of the child developing
electrolyte
An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...
imbalances,
metabolic acidosis
Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...
,
megaloblastic anemia
Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA replication, DNA synthesis during red blood cell production. ...
, and a host of
allergic reactions
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
.
Food product for humans
In many cultures, especially in
the West
West is a cardinal direction or compass point.
West or The West may also refer to:
Geography and locations
Global context
* The Western world
* Western culture and Western civilization in general
* The Western Bloc, countries allied with NATO ...
, humans continue to consume milk beyond infancy, using the milk of other mammals (especially cattle, goats and sheep) as a food product. Initially, the ability to digest milk was limited to children as adults did not produce
lactase
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives m ...
, an enzyme necessary for digesting the lactose in milk. People therefore converted milk to
curd
Curd is obtained by coagulating milk in a sequential process called curdling. It can be a final dairy product or the first stage in cheesemaking. The coagulation can be caused by adding rennet or any edible acidic substance such as l ...
, cheese, and other products to reduce the levels of lactose. Thousands of years ago, a chance mutation spread in human populations in northwestern Europe that enabled the production of lactase in adulthood. This mutation allowed milk to be used as a new source of nutrition which could sustain populations when other food sources failed. Milk is processed into a variety of products such as
cream
Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process ...
,
butter
Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment ...
,
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
,
kefir
Kefir ( ; also spelled as kephir or kefier; ; ; ) is a fermented milk drink similar to a thin yogurt or ayran that is made from kefir grains, a specific type of mesophilic symbiotic culture. The drink originated in the North Caucasus, in pa ...
,
ice cream
Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as str ...
, and
cheese
Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...
. Modern industrial processes use milk to produce
casein
Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of ...
,
whey protein
Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Glycomacropeptide also ma ...
, lactose,
condensed milk
Condensed milk is cow's milk from which water has been removed (roughly 60% of it). It is most often found with sugar added, in the form of ''sweetened condensed milk'' (SCM), to the extent that the terms "condensed milk" and "sweetened condens ...
,
powdered milk
Powdered milk, also called milk powder, dried milk, or dry milk, is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and do ...
, and many other food-additives and industrial products.
Whole milk, butter, and cream have high levels of
saturated fat
A saturated fat is a type of fat in which the fatty acid chains have all single bonds. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched c ...
. The sugar lactose is found only in milk, and possibly in
forsythia
''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is ...
flowers and a few tropical shrubs. Lactase, the enzyme needed to digest lactose, reaches its highest levels in the human small intestine immediately after birth, and then begins a slow decline unless milk is consumed regularly. Those groups who continue to tolerate milk have often exercised great creativity in using the milk of
domesticated
Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. A ...
ungulate
Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...
s, not only cattle, but also sheep, goats,
yak
The domestic yak (''Bos grunniens''), also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Kachin Sta ...
s,
water buffalo
The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, So ...
, horses,
reindeer
Reindeer (in North American English, known as caribou if wild and ''reindeer'' if domesticated) are deer in the genus ''Rangifer''. For the last few decades, reindeer were assigned to one species, ''Rangifer tarandus'', with about 10 subspe ...
and
camels
A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. ...
. India is the largest producer and consumer of cattle- and buffalo milk in the world.
History
Humans first learned to consume the milk of other mammals regularly following the domestication of animals during the
Neolithic Revolution
The Neolithic Revolution, or the (First) Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period from a lifestyle of hunting and gathering to one of agriculture and settlement, making an incre ...
or the development of agriculture. This development occurred independently in several global locations from as early as 9000–7000BC in
Mesopotamia
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the F ...
to 3500–3000BC in the Americas. People first domesticated the most important dairy animals – cattle, sheep and goats – in Southwest Asia, although domestic cattle had been independently derived from wild
aurochs
The aurochs (''Bos primigenius'') ( or ) is an extinct cattle species, considered to be the wild ancestor of modern domestic cattle. With a shoulder height of up to in bulls and in cows, it was one of the largest herbivores in the Holocen ...
populations several times since. Initially animals were kept for meat, and archaeologist
Andrew Sherratt
Andrew George Sherratt (8 May 1946 – 24 February 2006) was an English archaeologist, one of the most influential of his generation. He was best known for his theory of the secondary products revolution.
Early life and education
Sherratt was ...
has suggested that dairying, along with the exploitation of domestic animals for hair and labor, began much later in a separate
secondary products revolution
Andrew Sherratt's model of a secondary products revolution involved a widespread and broadly contemporaneous set of innovations in Old World farming. The use of domestic animals for primary carcass products (meat) was broadened from the 4th–3rd m ...
in the fourth millennium BC. Sherratt's model is not supported by recent findings, based on the analysis of
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
residue in prehistoric pottery, that shows that dairying was practiced in the early phases of agriculture in Southwest Asia, by at least the seventh millennium BC.
From Southwest Asia domestic dairy animals spread to Europe (beginning around 7000 BC but did not reach Britain and Scandinavia until after 4000 BC), and South Asia (7000–5500 BC). The first farmers in central Europe and Britain milked their animals.
Pastoral
A pastoral lifestyle is that of shepherds herding livestock around open areas of land according to seasons and the changing availability of water and pasture. It lends its name to a genre of literature, art, and music (pastorale) that depicts ...
and pastoral nomadic economies, which rely predominantly or exclusively on domestic animals and their products rather than crop farming, were developed as European farmers moved into the
Pontic–Caspian steppe
The Pontic–Caspian steppe, formed by the Caspian steppe and the Pontic steppe, is the steppeland stretching from the northern shores of the Black Sea (the Pontus Euxinus of antiquity) to the northern area around the Caspian Sea. It extends ...
in the fourth millennium BC, and subsequently spread across much of the
Eurasian steppe
The Eurasian Steppe, also simply called the Great Steppe or the steppes, is the vast steppe ecoregion of Eurasia in the temperate grasslands, savannas and shrublands biome. It stretches through Hungary, Bulgaria, Romania, Moldova and Transnistri ...
. Sheep and goats were introduced to Africa from Southwest Asia, but African cattle may have been independently domesticated around 7000–6000BC. Camels, domesticated in central Arabia in the fourth millennium BC, have also been used as dairy animals in North Africa and the Arabian Peninsula. The earliest Egyptian records of burn treatments describe burn dressings using milk from mothers of male babies. In the rest of the world (i.e., East and Southeast Asia, the Americas and Australia) milk and dairy products were historically not a large part of the diet, either because they remained populated by
hunter-gatherers
A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, ...
who did not keep animals or the local agricultural economies did not include domesticated dairy species. Milk consumption became common in these regions comparatively recently, as a consequence of European
colonialism
Colonialism is a practice or policy of control by one people or power over other people or areas, often by establishing colonies and generally with the aim of economic dominance. In the process of colonisation, colonisers may impose their relig ...
and political domination over much of the world in the last 500 years.
In the
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
, milk was called the "virtuous white liquor" because alcoholic beverages were safer to consume than the water generally available. Incorrectly thought to be blood diverted from the womb to the breast, it was also known as "white blood", and treated like blood for religious dietary purposes and in
humoral theory
Humorism, the humoral theory, or humoralism, was a system of medicine detailing a supposed makeup and workings of the human body, adopted by Ancient Greek and Roman physicians and philosophers.
Humorism began to fall out of favor in the 1850s ...
George Weymouth
George Weymouth (Waymouth) () was an English explorer of the area now occupied by the state of Maine.
Voyages
George Weymouth was a native of Cockington, Devon, who spent his youth studying shipbuilding and mathematics.
In 1602 Weymouth was ...
to New England did report the Wabanaki people Weymouth captured in Maine did report milking "Rain-Deere and Fallo-Deere." But Journalist Avery Yale Kamila and food historians said Rosier "misinterpreted the evidence." Historians report the Wabanaki did not domesticate deer. The tribes of the northern woodlands have historically been making nut milk. Cows were imported to
New England
New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
in 1624.
Industrialization
The growth in urban population, coupled with the expansion of the railway network in the mid-19th century, brought about a revolution in milk production and supply. Individual railway firms began transporting milk from rural areas to London from the 1840s and 1850s. Possibly the first such instance was in 1846, when
St Thomas's Hospital
St Thomas' Hospital is a large NHS teaching hospital in Central London, England. It is one of the institutions that compose the King's Health Partners, an academic health science centre. Administratively part of the Guy's and St Thomas' NHS Foun ...
in
Southwark
Southwark ( ) is a district of Central London situated on the south bank of the River Thames, forming the north-western part of the wider modern London Borough of Southwark. The district, which is the oldest part of South London, developed ...
contracted with milk suppliers outside London to ship milk by rail. The
Great Western Railway
The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
was an early and enthusiastic adopter, and began to transport milk into London from
Maidenhead
Maidenhead is a market town in the Royal Borough of Windsor and Maidenhead in the county of Berkshire, England, on the southwestern bank of the River Thames. It had an estimated population of 70,374 and forms part of the border with southern Bu ...
in 1860, despite much criticism. By 1900, the company was transporting over annually. The milk trade grew slowly through the 1860s, but went through a period of extensive, structural change in the 1870s and 1880s.
Urban demand began to grow, as consumer purchasing power increased and milk became regarded as a required daily commodity. Over the last three decades of the 19th century, demand for milk in most parts of the country doubled or, in some cases, tripled. Legislation in 1875 made the adulteration of milk illegal– This combined with a marketing campaign to change the image of milk. The proportion of rural imports by rail as a percentage of total milk consumption in London grew from under 5% in the 1860s to over 96% by the early 20th century. By that point, the supply system for milk was the most highly organized and integrated of any food product. Milk was analyzed for infection with
tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
. In 1907 180 samples were tested in Birmingham and 13.3% were found to be infected.
The first glass bottle packaging for milk was used in the 1870s. The first company to do so may have been the New York Dairy Company in 1877. The Express Dairy Company in England began glass bottle production in 1880. In 1884, Hervey Thatcher, an American inventor from New York, invented a glass
milk bottle
Glass milk bottles are glass bottles used for milk and they are generally reusable and returnable. Milk bottles are used mainly for doorstep delivery of fresh milk by milkmen as retail store sale is available in some regions (with bottle de ...
, called "Thatcher's Common Sense Milk Jar," which was sealed with a waxed paper disk. Later, in 1932,
plastic-coated paper Plastic-coated paper is a coated or laminated composite material made of paper or paperboard with a plastic layer or treatment on a surface. This type of coated paper is most used in the food and drink packaging industry.
Function
The plastic is u ...
milk cartons were introduced commercially.
In 1863, French chemist and biologist
Louis Pasteur
Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...
invented pasteurization, a method of killing harmful bacteria in beverages and food products."The History Of Milk"
About.com
Dotdash Meredith (formerly About.com) is an American digital media company based in New York City. The company publishes online articles and videos about various subjects across categories including health, home, food, finance, tech, beauty, ...
. Retrieved August 13, 2010. He developed this method while on summer vacation in Arbois, to remedy the frequent acidity of the local wines. He found out experimentally that it is sufficient to heat a young wine to only about for a brief time to kill the microbes, and that the wine could be nevertheless properly
aged
Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In ...
without sacrificing the final quality. In honor of Pasteur, the process became known as "pasteurization". Pasteurization was originally used as a way of preventing wine and beer from souring. Commercial pasteurizing equipment was produced in Germany in the 1880s, and producers adopted the process in
Copenhagen
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
and
Stockholm
Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...
by 1885.
Sources
The females of all mammal species can, by definition, produce milk, but cow's milk dominates commercial production. In 2011, FAO estimates 85% of all milk worldwide was produced from cows. Human milk is not produced or distributed industrially or commercially; however,
human milk bank
A human milk bank, breast milk bank or lactarium is a service that collects, screens, processes, and dispenses by prescription human milk donated by nursing mothers who are not biologically related to the recipient infant. The optimum nutrition ...
s collect donated human
breastmilk
Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by mammary glands located in the breast of a human female. Breast milk is the primary source of nutrition for newborns, containing fat, protein, carbohydrates (lactos ...
and redistribute it to infants who may benefit from human milk for various reasons (premature neonates, babies with allergies,
metabolic diseases
Inborn errors of metabolism form a large class of genetic diseases involving congenital disorders of enzyme activities. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances ( substra ...
, etc.) but who cannot breastfeed.
In the Western world, cow's milk is produced on an industrial scale and is, by far, the most commonly consumed form of milk. Commercial dairy farming using automated milking equipment produces the vast majority of milk in
developed countries
A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...
.
Dairy cattle
Dairy cattle (also called dairy cows) are cattle bred for the ability to produce large quantities of milk, from which dairy products are made. Dairy cattle generally are of the species ''Bos taurus''.
Historically, little distinction was mad ...
, such as the
Holstein
Holstein (; nds, label=Northern Low Saxon, Holsteen; da, Holsten; Latin and historical en, Holsatia, italic=yes) is the region between the rivers Elbe and Eider. It is the southern half of Schleswig-Holstein, the northernmost state of German ...
, have been bred selectively for increased milk production. About 90% of the dairy cows in the United States and 85% in
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
are Holsteins. Other dairy cows in the United States include
Ayrshire
Ayrshire ( gd, Siorrachd Inbhir Àir, ) is a historic county and registration county in south-west Scotland, located on the shores of the Firth of Clyde. Its principal towns include Ayr, Kilmarnock and Irvine and it borders the counties of Re ...
Guernsey
Guernsey (; Guernésiais: ''Guernési''; french: Guernesey) is an island in the English Channel off the coast of Normandy that is part of the Bailiwick of Guernsey, a British Crown Dependency.
It is the second largest of the Channel Islands ...
,
Jersey
Jersey ( , ; nrf, Jèrri, label=Jèrriais ), officially the Bailiwick of Jersey (french: Bailliage de Jersey, links=no; Jèrriais: ), is an island country and self-governing Crown Dependencies, Crown Dependency near the coast of north-west F ...
and
Milking Shorthorn
The Dairy Shorthorn is a British list of cattle breeds, breed of dairy cattle. It derives from the Shorthorn cattle of Tees-side, in the North Riding of Yorkshire and in Northumbria (now divided between County Durham and Northumberland) in nor ...
(Dairy Shorthorn).
Other animal-based sources
Aside from cattle, many kinds of livestock provide milk used by humans for dairy products. These animals include
water buffalo
The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, So ...
,
goat
The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
,
sheep
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...
,
camel
A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
,
donkey
The domestic donkey is a hoofed mammal in the family Equidae, the same family as the horse. It derives from the African wild ass, ''Equus africanus'', and may be classified either as a subspecies thereof, ''Equus africanus asinus'', or as a ...
,
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...
, reindeer and yak. The first four respectively produced about 11%, 2%, 1.4% and 0.2% of all milk worldwide in 2011.
In Russia and Sweden, small moose dairies also exist.
According to the US National Bison Association,
American bison
The American bison (''Bison bison'') is a species of bison native to North America. Sometimes colloquially referred to as American buffalo or simply buffalo (a different clade of bovine), it is one of two extant species of bison, alongside the ...
(also called American buffalo) are not milked commercially; however, various sources report cows resulting from cross-breeding bison and domestic cattle are good milk producers, and have been used both during the European settlement of North America and during the development of commercial
Beefalo
Beefalo constitute a hybrid offspring of domestic cattle (''Bos taurus''), usually a male in managed breeding programs, and the American bison (''Bison bison''), usually a female in managed breeding programs. The breed was created to combine the ...
in the 1970s and 1980s.
Swine are almost never milked, even though their milk is similar to cow's milk and perfectly suitable for human consumption. The main reasons for this are that milking a sow's numerous small teats is very cumbersome, and that sows can not store their milk as cows can. A few pig farms do sell pig cheese as a novelty item; these cheeses are exceedingly expensive.
Production worldwide
In 2012, the largest producer of milk and milk products was India followed by the United States of America, China, Pakistan and Brazil. All 28 European Union members together produced of milk in 2013, the largest by any
politico
''Politico'' (stylized in all caps), known originally as ''The Politico'', is an American, German-owned political journalism newspaper company based in Arlington County, Virginia, that covers politics and policy in the United States and intern ...
-
economic
An economy is an area of the Production (economics), production, Distribution (economics), distribution and trade, as well as Consumption (economics), consumption of Goods (economics), goods and Service (economics), services. In general, it is ...
union.
Increasing affluence in developing countries, as well as increased promotion of milk and milk products, has led to a rise in milk consumption in developing countries in recent years. In turn, the opportunities presented by these growing markets have attracted investments by multinational dairy firms. Nevertheless, in many countries production remains on a small scale and presents significant opportunities for diversification of income sources by small farms. Local milk collection centers, where milk is collected and chilled prior to being transferred to urban dairies, are a good example of where farmers have been able to work on a
cooperative
A cooperative (also known as co-operative, co-op, or coop) is "an autonomous association of persons united voluntarily to meet their common economic, social and cultural needs and aspirations through a jointly owned and democratically-control ...
basis, particularly in countries such as India.
Production yields
FAO reports Israel dairy farms are the most productive in the world, with a yield of milk per cow per year. This survey over 2001 and 2007 was conducted by ICAR (International Committee for Animal Recording) across 17 developed countries. The survey found that the average herd size in these developed countries increased from 74 to 99 cows per herd between 2001 and 2007. A dairy farm had an average of 19 cows per herd in Norway, and 337 in New Zealand. Annual milk production in the same period increased from per cow in these developed countries. The lowest average production was in New Zealand at per cow. The milk yield per cow depended on production systems, nutrition of the cows, and only to a minor extent different genetic potential of the animals. What the cow ate made the most impact on the production obtained. New Zealand cows with the lowest yield per year grazed all year, in contrast to Israel with the highest yield where the cows ate in barns with an energy-rich mixed diet.
The milk yield per cow in the United States was per year in 2010. In contrast, the milk yields per cow in India and China– the second and third largest producers– were respectively and per year.
Price
It was reported in 2007 that with increased worldwide prosperity and the competition of bio-fuel production for feed stocks, both the demand for and the price of milk had substantially increased worldwide. Particularly notable was the rapid increase of consumption of milk in China and the rise of the price of milk in the United States above the government subsidized price. In 2010 the Department of Agriculture predicted farmers would receive an average of of cow's milk, which is down from 2007 and below the
break-even
Break-even (or break even), often abbreviated as B/E in finance, (sometimes called point of equilibrium) is the point of balance making neither a profit nor a loss. Any number below the break-even point constitutes a loss while any number above i ...
point for many cattle farmers.
Composition
Milk is an
emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althoug ...
or
colloid
A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...
of
butterfat
Butterfat or milkfat is the fatty portion of milk. Milk and cream are often sold according to the amount of butterfat they contain.
Composition
Butterfat is mainly composed of triglycerides. Each triglyceride contains three fatty acids. Butt ...
globules within a water-based fluid that contains dissolved
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
s and protein aggregates with minerals. Because it is produced as a food source for the young, all of its contents provide benefits for growth. The principal requirements are energy (lipids, lactose, and protein), biosynthesis of non-essential amino acids supplied by proteins (essential amino acids and amino groups), essential fatty acids, vitamins and inorganic elements, and water.Fox, P.F. Advanced Dairy Chemistry, Vol. 3: Lactose, Water, Salts and Vitamins. 2nd ed. Chapman and Hall: New York, 1995.
pH
The pH of milk ranges from 6.7 to 6.9. Milk from other bovines and non-bovine
mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
varies in composition, but has a similar pH.
Lipids
Initially milk fat is secreted in the form of a fat globule surrounded by a
membrane
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. B ...
.Fox, P.F. Advanced Dairy Chemistry: Vol 2 Lipids. 2nd Ed. Chapman and Hall: New York, 1995. Each fat globule is composed almost entirely of triacylglycerols and is surrounded by a membrane consisting of complex lipids such as
phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...
s, along with proteins. These act as
emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...
s which keep the individual globules from coalescing and protect the contents of these globules from various
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s in the fluid portion of the milk. Although 97–98% of lipids are triacylglycerols, small amounts of di- and monoacylglycerols, free cholesterol and cholesterol esters, free fatty acids, and phospholipids are also present. Unlike protein and carbohydrates, fat composition in milk varies widely due to genetic, lactational, and nutritional factor difference between different species.
Like composition, fat globules vary in size from less than 0.2 to about 15
micrometers
The micrometre (American and British English spelling differences#-re, -er, international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American and British English spelling differences# ...
in diameter between different species. Diameter may also vary between animals within a species and at different times within a milking of a single animal. In unhomogenized cow's milk, the fat globules have an average diameter of two to four micrometers and with homogenization, average around 0.4 micrometers. The
fat-soluble
Lipophilicity (from Greek λίπος "fat" and φίλος "friendly"), refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipop ...
vitamins A, D, E, and K along with essential fatty acids such as linoleic and linolenic acid are found within the milk fat portion of the milk.
Proteins
Normal bovine milk contains 30–35 grams of protein per liter of which about 80% is arranged in casein
micelles
A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloid, colloidal suspension (also known as associat ...
. Total proteins in milk represent 3.2% of its composition (nutrition table).
Caseins
The largest structures in the fluid portion of the milk are "casein micelles": aggregates of several thousand protein molecules with superficial resemblance to a surfactant
micelle
A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated collo ...
, bonded with the help of nanometer-scale particles of
calcium phosphate
The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white ...
. Each casein micelle is roughly spherical and about a tenth of a micrometer across. There are four different types of casein proteins: αs1-, αs2-, β-, and κ-caseins. Most of the casein proteins are bound into the micelles. There are several competing theories regarding the precise structure of the micelles, but they share one important feature: the outermost layer consists of strands of one type of protein,
k-casein
Κ-casein, or kappa casein, is a mammalian milk protein involved in several important physiological processes. Chymosin splits K-casein into an insoluble peptide (para kappa-casein) and water-soluble glycomacropeptide (GMP). GMP is responsible f ...
, reaching out from the body of the micelle into the surrounding fluid. These kappa-casein molecules all have a negative
electrical charge
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
and therefore repel each other, keeping the micelles separated under normal conditions and in a stable
colloid
A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...
al
suspension
Suspension or suspended may refer to:
Science and engineering
* Suspension (topology), in mathematics
* Suspension (dynamical systems), in mathematics
* Suspension of a ring, in mathematics
* Suspension (chemistry), small solid particles suspend ...
in the water-based surrounding fluid.
Milk contains dozens of other types of proteins beside caseins and including enzymes. These other proteins are more water-soluble than caseins and do not form larger structures. Because the proteins remain suspended in
whey
Whey is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types of hard ...
remaining when caseins coagulate into curds, they are collectively known as ''whey proteins''.
Lactoglobulin
β-Lactoglobulin (BLG) is the major whey protein of cow and sheep's milk (~3 g/L), and is also present in many other mammalian species; a notable exception being humans. Its structure, properties and biological role have been reviewed many times. ...
is the most common whey protein by a large margin. The ratio of caseins to whey proteins varies greatly between species; for example, it is 82:18 in cows and around 32:68 in humans.
Salts, minerals, and vitamins
Minerals or milk salts, are traditional names for a variety of cations and anions within bovine milk. Calcium, phosphate, magnesium, sodium, potassium, citrate, and chloride are all included and they typically occur at concentrations of 5–40 mM. The milk salts strongly interact with casein, most notably calcium phosphate. It is present in excess and often, much greater excess of solubility of solid calcium phosphate. In addition to calcium, milk is a good source of many other vitamins. Vitamins A, B6, B12, C, D, K, E, thiamine, niacin, biotin, riboflavin, folates, and pantothenic acid are all present in milk.
Calcium phosphate structure
For many years the most widely accepted theory of the structure of a micelle was that it was composed of spherical casein aggregates, called submicelles, that were held together by calcium phosphate linkages. However, there are two recent models of the casein micelle that refute the distinct micellular structures within the micelle.
The first theory, attributed to de Kruif and Holt, proposes that nanoclusters of calcium phosphate and the phosphopeptide fraction of beta-casein are the centerpiece to micellar structure. Specifically in this view unstructured proteins organize around the calcium phosphate, giving rise to their structure, and thus no specific structure is formed.
Under the second theory, proposed by Horne, the growth of calcium phosphate nanoclusters begins the process of micelle formation, but is limited by binding phosphopeptide loop regions of the caseins. Once bound, protein-protein interactions are formed and polymerization occurs, in which K-casein is used as an end cap to form micelles with trapped calcium phosphate nanoclusters.
Some sources indicate that the trapped calcium phosphate is in the form of Ca9(PO4)6;
whereas others say it is similar to the structure of the mineral
brushite
Brushite is a phosphate mineral with the chemical formula . Crystals of the pure compound belong to the monoclinic space group C2/c and are colorless.
Milk contains several different
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
including
lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix '' - ...
,
glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
,
galactose
Galactose (, '' galacto-'' + '' -ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molec ...
, and other oligosaccharides. The lactose gives milk its sweet taste and contributes approximately 40% of whole cow's milk's calories. Lactose is a disaccharide composite of two
simple sugars
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...
,
glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
and
galactose
Galactose (, '' galacto-'' + '' -ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molec ...
. Bovine milk averages 4.8% anhydrous lactose, which amounts to about 50% of the total solids of skimmed milk. Levels of lactose are dependent upon the type of milk as other carbohydrates can be present at higher concentrations than lactose in milks.
Miscellaneous contents
Other components found in raw cow's milk are living
white blood cell
White blood cells, also called leukocytes or leucocytes, are the cell (biology), cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and de ...
s, mammary gland cells, various bacteria, vitamin C, and a large number of active enzymes.
Appearance
Both the fat globules and the smaller casein micelles, which are just large enough to deflect light, contribute to the opaque white color of milk. The fat globules contain some yellow-orange carotene, enough in some breeds (such as Guernsey and Jersey cattle) to impart a golden or "creamy" hue to a glass of milk. The
riboflavin
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...
in the whey portion of milk has a greenish color, which sometimes can be discerned in skimmed milk or whey products. Fat-free skimmed milk has only the casein micelles to scatter light, and they tend to scatter shorter-wavelength blue light more than they do red, giving skimmed milk a bluish tint.
Processing
In most Western countries, centralized dairy facilities process milk and products obtained from milk, such as cream, butter, and cheese. In the US, these dairies usually are local companies, while in the Southern Hemisphere facilities may be run by large multi-national corporations such as
Fonterra
Fonterra Co-operative Group Limited is a New Zealand multinational publicly traded dairy co-operative owned by around 9,000 New Zealand farmers. The company is responsible for approximately 30% of the world's dairy exports and with revenue exce ...
.
Pasteurization
Pasteurization is used to kill harmful
pathogenic bacteria
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often Probiotic, beneficial but others can cause infectious diseases. The n ...
such as '' M. paratuberculosis'' and '' E. coli 0157:H7'' by heating the milk for a short time and then immediately cooling it. Types of pasteurized milk include full cream, reduced fat, skim milk, calcium enriched, flavored, and UHT. The standard high temperature short time (HTST) process of for 15 seconds completely kills pathogenic bacteria in milk, rendering it safe to drink for up to three weeks if continually refrigerated. Dairies print
best before
Best or The Best may refer to:
People
* Best (surname), people with the surname Best
* Best (footballer, born 1968), retired Portuguese footballer
Companies and organizations
* Best & Co., an 1879–1971 clothing chain
* Best Lock Corporation ...
dates on each container, after which stores remove any unsold milk from their shelves.
A side effect of the heating of pasteurization is that some vitamin and mineral content is lost. Soluble calcium and phosphorus decrease by 5%, thiamin and vitamin B12 by 10%, and
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
by 20% or greater (even to complete loss). Because losses are small in comparison to the large amount of the two B-vitamins present, milk continues to provide significant amounts of thiamin and vitamin B12. The loss of vitamin C is not nutritionally significant in a well-balanced diet, as milk is not an important dietary source of vitamin C.
Filtration
Microfiltration
Microfiltration is a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane filter to separate microorganisms and suspended particles from process liquid. It is commonly used in conjunction ...
is a process that partially replaces pasteurization and produces milk with fewer microorganisms and longer shelf life without a change in the taste of the milk. In this process, cream is separated from the skimmed milk and is pasteurized in the usual way, but the skimmed milk is forced through ceramic microfilters that trap 99.9% of microorganisms in the milk (as compared to 99.999% killing of microorganisms in standard HTST pasteurization). The skimmed milk then is recombined with the pasteurized cream to reconstitute the original milk composition.
Ultrafiltration
Ultrafiltration (UF) is a variety of membrane filtration in which forces such as pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the s ...
uses finer filters than microfiltration, which allow lactose and water to pass through while retaining fats, calcium and protein. As with microfiltration, the fat may be removed before filtration and added back in afterwards.
Ultrafiltered milk
Ultrafiltered milk, also known as UF milk, UF skim, or diafiltered milk, is a subclassification of milk protein concentrate that is produced by passing milk under pressure through a thin, porous membrane to separate the components of milk according ...
is used in cheesemaking, since it has reduced volume for a given protein content, and is sold directly to consumers as a higher protein, lower sugar content, and creamier alternative to regular milk.
Creaming and homogenization
Upon standing for 12 to 24 hours, fresh milk has a tendency to separate into a high-fat cream layer on top of a larger, low-fat milk layer. The cream often is sold as a separate product with its own uses. Today the separation of the cream from the milk usually is accomplished rapidly in centrifugal
cream separator
A separator is a centrifugal device that separates milk into cream and skimmed milk. Separation was commonly performed on farms in the past. Most farmers milked a few cows, usually by hand, and separated milk. Some of the skimmed milk was consum ...
s. The fat globules rise to the top of a container of milk because fat is less dense than water.
The smaller the globules, the more other molecular-level forces prevent this from happening. The cream rises in cow's milk much more quickly than a simple model would predict: rather than isolated globules, the fat in the milk tends to form into clusters containing about a million globules, held together by a number of minor whey proteins. These clusters rise faster than individual globules can. The fat globules in milk from goats, sheep, and water buffalo do not form clusters as readily and are smaller to begin with, resulting in a slower separation of cream from these milks.
Milk often is
homogenized
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
, a treatment that prevents a cream layer from separating out of the milk. The milk is pumped at high pressures through very narrow tubes, breaking up the fat globules through
turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...
and
cavitation
Cavitation is a phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, cal ...
. A greater number of smaller particles possess more total
surface area
The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc ...
than a smaller number of larger ones, and the original fat globule membranes cannot completely cover them. Casein micelles are attracted to the newly exposed fat surfaces.
Nearly one-third of the micelles in the milk end up participating in this new membrane structure. The casein weighs down the globules and interferes with the clustering that accelerated separation. The exposed fat globules are vulnerable to certain enzymes present in milk, which could break down the fats and produce rancid flavors. To prevent this, the enzymes are inactivated by pasteurizing the milk immediately before or during homogenization.
Homogenized milk tastes blander but feels creamier in the mouth than unhomogenized. It is whiter and more resistant to developing off flavors. Creamline (or cream-top) milk is unhomogenized. It may or may not have been pasteurized. Milk that has undergone high-pressure homogenization, sometimes labeled as "ultra-homogenized", has a longer
shelf life
Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or no longer on a ...
than milk that has undergone ordinary homogenization at lower pressures.
UHT
Ultra Heat Treatment (UHT) is a type of milk processing where all bacteria are destroyed with high heat to extend its shelf life for up to 6 months, as long as the package is not opened. Milk is firstly homogenized and then is heated to 138 degrees Celsius for 1–3seconds. The milk is immediately cooled down and packed into a sterile container. As a result of this treatment, all the pathogenic bacteria within the milk are destroyed, unlike when the milk is just pasteurized. The treated milk will keep for up for 6 months if unopened. UHT milk does not need to be refrigerated until the package is opened, which makes it easier to ship and store. However, in this process there is a loss of
vitamin B1
Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thia ...
and
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
, and there is also a slight change in the taste of the milk.
Nutrition and health
The composition of milk differs widely among species. Factors such as the type of protein; the proportion of protein, fat, and sugar; the levels of various vitamins and minerals; and the size of the butterfat globules, and the strength of the curd are among those that may vary. For example:
*
Human milk
Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by mammary glands located in the breast of a human female. Breast milk is the primary source of nutrition for newborns, containing fat, protein, carbohydrates (lacto ...
contains, on average, 1.1% protein, 4.2% fat, 7.0% lactose (a sugar), and supplies 72 kcal of energy per 100 grams.
* Cow's milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7%
minerals
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
and supplies 66 kcal of energy per 100 grams. See also
Nutritional value Nutritional value or nutritive value as part of food quality is the measure of a well-balanced ratio of the essential nutrients carbohydrates, fat, protein, minerals, and vitamins in items of food or diet concerning the nutrient requirements of the ...
further on in this article and more complete lists at online sources that list values and differences in categories.
Donkey and horse milk have the lowest fat content, while the milk of
seals
Seals may refer to:
* Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
** Earless seal, or "true seal"
** Fur seal
* Seal (emblem), a device to impress an emblem, used as a means of a ...
and whales may contain more than 50% fat.
Cow's milk: variation by breed
These compositions vary by breed, animal, and point in the lactation period.
The protein range for these four breeds is 3.3% to 3.9%, while the lactose range is 4.7% to 4.9%.
Milk fat percentages may be manipulated by dairy farmers' stock diet formulation strategies. The infection known as
mastitis
Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...
Processed cow's milk was formulated to contain differing amounts of fat during the 1950s. One cup (250 mL) of 2%-fat cow's milk contains 285 mg of
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
, which represents 22% to 29% of the
daily recommended intake
The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the National Academy of Medicine (NAM) of the National Academies (United States). It was introduced in 1997 in order to broaden the existing guidelines known as Rec ...
(DRI) of calcium for an adult. Depending on its age, milk contains 8 grams of
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
, and a number of other nutrients (either naturally or through
fortification
A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...
).
Allergy
One of the most common
food allergies
A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure ...
in infants is to cow's milk. This is an immunologically mediated adverse reaction, rarely fatal, to one or more cow's milk proteins. Milk allergy affects between 2% and 3% of babies and young children. To reduce risk, recommendations are that babies should be exclusively
breastfed
Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
for at least four months, preferably six months, before introducing cow's milk. The majority of children outgrow milk allergy, but for about 0.4% the condition persists into adulthood.
Lactose intolerance
Lactose intolerance is a condition in which people have symptoms due to deficiency or absence of the enzyme
lactase
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives m ...
in the
small intestine
The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...
, causing poor absorption of milk lactose. People affected vary in the amount of lactose they can tolerate before symptoms develop, which may include abdominal pain,
bloating
Abdominal bloating (or simply bloating) is a short-term disease that affects the gastrointestinal tract. Bloating is generally characterized by an excess buildup of gas, air or fluids in the stomach. A person may have feelings of tightness, press ...
,
diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
, gas, and
nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
. Severity depends on the amount of milk consumed. Those affected are usually able to drink at least one cup of milk without developing significant symptoms, with greater amounts tolerated if drunk with a meal or throughout the day.
Evolution of lactation
The
mammary gland
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primat ...
is thought to have derived from
apocrine
Apocrine () glands are a type of exocrine gland, which are themselves a type of gland, i.e. a group of cells specialized for the release of secretions. Exocrine glands secrete by one of three means: holocrine, merocrine and apocrine. In apocri ...
skin glands. It has been suggested that the original function of lactation (milk production) was keeping eggs moist. Much of the argument is based on
monotreme
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brain ...
s (egg-laying mammals). The original adaptive significance of milk secretions may have been nutrition or immunological protection. This secretion gradually became more copious and accrued nutritional complexity over evolutionary time.
Tritylodontid
Tritylodontidae ("three-knob teeth", named after the shape of their cheek teeth) is an extinct family of small to medium-sized, highly specialized mammal-like cynodonts, bearing several mammalian traits like erect limbs, endothermy and details ...
cynodont
The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...
s seem to have displayed lactation, based on their dental replacement patterns.
Bovine growth hormone supplementation
Since November 1993,
recombinant bovine somatotropin
Bovine somatotropin or bovine somatotrophin (abbreviated bST and BST), or bovine growth hormone (BGH), is a peptide hormone produced by cows' pituitary glands.
Like other hormones, it is produced in small quantities and is used in regulating m ...
(rbST), also called rBGH, has been sold to dairy farmers with
FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
approval. Cows produce bovine growth hormone naturally, but some producers administer an additional recombinant version of BGH which is produced through
genetically engineered
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
E. coli to increase milk production. Bovine growth hormone also stimulates liver production of
insulin-like growth factor 1
Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults.
IGF-1 is a protein that in humans is ...
(IGF1). The US
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
, the
National Institutes of Health
The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...
and the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
have reported that both of these compounds are safe for human consumption at the amounts present.
Milk from cows given rBST may be sold in the United States, and the FDA stated that no significant difference has been shown between milk derived from rBST-treated and that from non-rBST-treated cows. Milk that advertises that it comes from cows not treated with rBST, is required to state this finding on its label.
Cows receiving rBGH supplements may more frequently contract an udder infection known as
mastitis
Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...
. Problems with mastitis have led to Canada, Australia, New Zealand, and Japan banning milk from rBST treated cows. Mastitis, among other diseases, may be responsible for the fact that levels of
white blood cell
White blood cells, also called leukocytes or leucocytes, are the cell (biology), cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and de ...
s in milk vary naturally.
rBGH is also banned in the European Union, for reasons of animal welfare.
Varieties and brands
Milk products are sold in a number of varieties based on types/degrees of:
* additives (e.g. vitamins, flavorings)
* age (e.g. cheddar, old cheddar)
* coagulation (e.g. cottage cheese)
* farming method (e.g. organic, grass-fed,
haymilk
Haymilk (german: Heumilch, it, latte fieno) is dairy milk produced from animals that have mainly been fed fresh grass and (dry) hay, rather than fermented fodder. The milk is thus produced according to the tradition in the Alps. The term hay milk ...
)
* fat content (e.g. half and half, 3% fat milk, 2% milk, 1% milk, skim milk)
* fermentation (e.g. buttermilk)
* flavoring (e.g. chocolate and strawberry)
* homogenization (e.g. cream top)
* packaging (e.g. bottle, carton, bag)
* pasteurization (e.g. raw milk, pasteurized milk)
* reduction or elimination of lactose
* species (e.g. cow, goat, sheep)
* sweetening (e.g., chocolate and strawberry milk)
* water content (e.g. dry milk powder, condensed milk, ultrafiltered milk)
Milk preserved by the
UHT
Ultra-high temperature processing (UHT), ultra-heat treatment, or ultra-pasteurization is a food processing technology that sterilizes liquid food by heating it above – the temperature required to kill bacterial endospores – for 2 ...
process does not need to be refrigerated before opening and has a much longer shelf life (six months) than milk in ordinary packaging. It is typically sold unrefrigerated in the UK, US, Europe, Latin America, and Australia.
Reduction or elimination of lactose
Lactose-free milk can be produced by passing milk over lactase enzyme bound to an inert carrier. Once the molecule is cleaved, there are no lactose ill effects. Forms are available with reduced amounts of lactose (typically 30% of normal), and alternatively with nearly 0%. The only noticeable difference from regular milk is a slightly sweeter taste due to the cleavage of lactose into glucose and galactose. Lactose-reduced milk can also be produced via ultra filtration, which removes smaller molecules such as lactose and water while leaving calcium and proteins behind. Milk produced via these methods has a lower sugar content than regular milk. To aid digestion in those with
lactose intolerance
Lactose intolerance is a common condition caused by a decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pa ...
, another alternative is dairy foods, milk and
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
, with added bacterial cultures such as ''
Lactobacillus acidophilus
''Lactobacillus acidophilus'' (New Latin 'acid-loving milk-bacillus') is a rod-shaped, Gram-positive, homofermentative, anaerobic microbe first isolated from infant feces in the year 1900. The species is most commonly found in humans, specifically ...
'' ("acidophilus milk") and
bifidobacteria
''Bifidobacterium'' is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract though strains have been isolated from the vagina and mouth ('' B. dentium'') of mamma ...
. Another milk with ''
Lactococcus lactis
''Lactococcus lactis'' is a Gram-positive bacterium used extensively in the production of buttermilk and cheese, but has also become famous as the first genetically modified organism to be used alive for the treatment of human disease. ''L. lact ...
'' bacteria cultures (" cultured buttermilk") often is used in cooking to replace the traditional use of naturally
soured milk
Soured milk denotes a range of food products produced by the acidification of milk. Acidification, which gives the milk a tart taste, is achieved either through bacterial fermentation or through the addition of an acid, such as lemon juice or vineg ...
, which has become rare due to the ubiquity of pasteurization, which also kills the naturally occurring Lactococcus bacteria.
Additives and flavoring
Commercially sold milk commonly has
vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
added to it to make up for lack of exposure to
UVB
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
radiation. Reduced-fat milks often have added
vitamin A palmitate
Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals.
An alternate spelling, retinol palmitate, which violates the - ...
to compensate for the loss of the vitamin during fat removal; in the United States this results in reduced fat milks having a higher vitamin A content than whole milk. Milk often has
flavoring
A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gusta ...
added to it for better taste or as a means of improving sales.
Chocolate milk
Chocolate milk is a type of flavoured milk made by mixing cocoa solids with milk (either dairy or plant-based). It is a food pairing in which the milk's mouthfeel masks the dietary fibres of the cocoa solids.
Types
The liquid carbohydr ...
has been sold for many years and has been followed more recently by
strawberry milk
Flavored milk is a sweetened dairy drink made with milk, sugar, flavorings, and sometimes food colorings. It may be sold as a pasteurized, refrigerated product, or as an ultra-high-temperature processing, ultra-high-temperature (UHT) treated produ ...
and others. Some nutritionists have criticized
flavored milk
Flavored milk is a sweetened dairy drink made with milk, sugar, flavorings, and sometimes food colorings. It may be sold as a pasteurized, refrigerated product, or as an ultra-high-temperature (UHT) treated product not requiring refrigeration. ...
for adding sugar, usually in the form of
high-fructose corn syrup
High-fructose corn syrup (HFCS), also known as glucose–fructose, isoglucose and glucose–fructose syrup, is a sweetener made from corn starch. As in the production of conventional corn syrup, the starch is broken down into glucose by enzy ...
, to the diets of children who are already commonly obese in the US.
Distribution
Due to the short shelf life of normal milk, it used to be delivered to households daily in many countries; however, improved refrigeration at home, changing food shopping patterns because of supermarkets, and the higher cost of home delivery mean that daily deliveries by a
milkman
Milk delivery is a delivery service dedicated to supplying milk. This service typically delivers milk in bottles or cartons directly to customers' homes. This service is performed by a milkman, milkwoman, or milk deliverer. (In contrast, a cow ...
are no longer available in most countries.
Australia and New Zealand
In Australia and
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, prior to
metrication
Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, countries have transitioned from local and traditional units of measurement to the metric system. This process began in F ...
, milk was generally distributed in 1 pint (568mL) glass bottles. In Australia and Ireland there was a government funded "free milk for school children" program, and milk was distributed at morning recess in 1/3 pint bottles. With the conversion to metric measures, the milk industry was concerned that the replacement of the pint bottles with 500mL bottles would result in a 13.6% drop in milk consumption; hence, all pint bottles were recalled and replaced by 600mL bottles. With time, due to the steadily increasing cost of collecting, transporting, storing and cleaning glass bottles, they were replaced by cardboard cartons. A number of designs were used, including a tetrahedron which could be close-packed without waste space, and could not be knocked over accidentally (slogan: "No more crying over spilt milk"). However, the industry eventually settled on a design similar to that used in the United States.Milk and Juice Cartons Fact Sheet Waste Wise WA, zerowastewa.com.au. Retrieved June 21, 2009.
Milk is now available in a variety of sizes in paperboard
milk carton
A carton is a box or container usually made of liquid packaging board, paperboard and sometimes of corrugated fiberboard.
Many types of cartons are used in packaging. Sometimes a carton is also called a box.
Types of cartons
Folding carton ...
s (250 mL, 375 mL, 600 mL, 1 liter and 1.5 liters) and
plastic bottle
A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, and ink. The size ranges from v ...
s (1, 2 and 3 liters). A significant addition to the marketplace has been "long-life" milk (
UHT
Ultra-high temperature processing (UHT), ultra-heat treatment, or ultra-pasteurization is a food processing technology that sterilizes liquid food by heating it above – the temperature required to kill bacterial endospores – for 2 ...
), generally available in 1 and 2 liter rectangular cardboard cartons. In urban and suburban areas where there is sufficient demand, home delivery is still available, though in suburban areas this is often 3 times per week rather than daily. Another significant and popular addition to the marketplace has been flavored milks; for example, as mentioned above,
Farmers Union Iced Coffee
Farmers Union Iced Coffee is a flavoured milk drink popular in Australia, primarily the state of South Australia. It continues to be sold under the "Farmers Union" banner, originally a South Australian co-operative, subsequently the listed compa ...
outsells
Coca-Cola
Coca-Cola, or Coke, is a carbonated soft drink manufactured by the Coca-Cola Company. Originally marketed as a temperance drink and intended as a patent medicine, it was invented in the late 19th century by John Stith Pemberton in Atlanta ...
in
South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
.
India
In rural
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, milk is home delivered, daily, by local milkmen carrying bulk quantities in a metal container, usually on a bicycle. In other parts of metropolitan
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, milk is usually bought or delivered in plastic bags or cartons via shops or supermarkets.
The current milk chain flow in India is from milk producer to milk collection agent. Then it is transported to a milk chilling center and bulk transported to the processing plant, then to the sales agent and finally to the consumer.
A 2011 survey by the Food Safety and Standards Authority of India found that nearly 70% of samples had not conformed to the standards set for milk. The study found that due to lack of hygiene and sanitation in milk handling and packaging, detergents (used during cleaning operations) were not washed properly and found their way into the milk. About 8% of samples in the survey were found to have detergents, which are hazardous to health.
Pakistan
In
Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
, milk is supplied in jugs. Milk has been a staple food, especially among the pastoral tribes in this country.
United Kingdom
Since the late 1990s, milk-buying patterns have changed drastically in the UK. The classic
milkman
Milk delivery is a delivery service dedicated to supplying milk. This service typically delivers milk in bottles or cartons directly to customers' homes. This service is performed by a milkman, milkwoman, or milk deliverer. (In contrast, a cow ...
, who travels his local
milk round The milkround is the term commonly used in the UK to describe the semester of companies touring colleges each year, in order to advertise their companies and recruit students.
An online university student website is also called Milkround, which is ...
(route) using a
milk float
A milk float is a vehicle specifically designed for the delivery of fresh milk. Today, milk floats are usually battery electric vehicles (BEV), but they were formerly horse-drawn floats. They were once common in many European countries, ...
(often battery powered) during the early hours and delivers milk in 1-
pint
The pint (, ; symbol pt, sometimes abbreviated as ''p'') is a unit of volume or capacity in both the imperial unit, imperial and United States customary units, United States customary measurement systems. In both of those systems it is tradition ...
glass bottles with
aluminum foil
Aluminium foil (or aluminum foil in North American English; often informally called tin foil) is aluminium prepared in thin metal leaves with a thickness less than ; thinner gauges down to are also commonly used. Standard household foil is typ ...
tops directly to households, has almost disappeared. Two of the main reasons for the decline of UK home deliveries by milkmen are household refrigerators (which lessen the need for daily milk deliveries) and private car usage (which has increased supermarket shopping). Another factor is that it is cheaper to purchase milk from a supermarket than from home delivery. In 1996, more than 2.5 billion liters of milk were still being delivered by milkmen, but by 2006 only 637 million liters (13% of milk consumed) was delivered by some 9,500 milkmen. By 2010, the estimated number of milkmen had dropped to 6,000. Assuming that delivery per milkman is the same as it was in 2006, this means milkmen deliveries now only account for 6–7% of all milk consumed by UK households (6.7 billion liters in 2008/2009).
Almost 95% of all milk in the UK is thus sold in shops today, most of it in plastic bottles of various sizes, but some also in
milk carton
A carton is a box or container usually made of liquid packaging board, paperboard and sometimes of corrugated fiberboard.
Many types of cartons are used in packaging. Sometimes a carton is also called a box.
Types of cartons
Folding carton ...
s. Milk is hardly ever sold in glass bottles in UK shops.
United States
In the United States, glass milk bottles have been replaced mostly with
milk carton
A carton is a box or container usually made of liquid packaging board, paperboard and sometimes of corrugated fiberboard.
Many types of cartons are used in packaging. Sometimes a carton is also called a box.
Types of cartons
Folding carton ...
s and plastic jugs. Gallons of milk are almost always sold in jugs, while half gallons and quarts may be found in both paper cartons and plastic jugs, and smaller sizes are almost always in cartons.
The "half pint" () milk carton is the traditional unit as a component of school lunches, though some companies have replaced that unit size with a plastic bottle, which is also available at retail in 6- and 12-pack size.
Packaging
Glass milk bottles are now rare. Most people purchase milk in bags, plastic bottles, or plastic-coated paper cartons.
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
(UV) light from
fluorescent lighting
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet ligh ...
can alter the flavor of milk, so many companies that once distributed milk in
transparent
Transparency, transparence or transparent most often refer to:
* Transparency (optics), the physical property of allowing the transmission of light through a material
They may also refer to:
Literal uses
* Transparency (photography), a still, ...
or highly
translucent
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions a ...
containers are now using thicker materials that block the UV light.
Milk comes in a variety of
containers
A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping.
Things kept inside of a container are protected on several sides by being inside of its structure. The term ...
with local variants:
;Argentina
: Commonly sold in 1-liter bags and cardboard boxes. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.
;Australia and New Zealand
: Distributed in a variety of sizes, most commonly in
aseptic
Asepsis is the state of being free from disease-causing micro-organisms (such as pathogenic bacteria, viruses, pathogenic fungi, and parasites). There are two categories of asepsis: medical and surgical. The modern day notion of asepsis is deriv ...
cartons for up to 1.5 liters, and plastic screw-top bottles beyond that with the following volumes; 1.1 L, 2 L, and 3 L. 1-liter
milk bag
A milk bag is a plastic bag that contains milk. Usually one of the corners is cut off to allow for pouring, and the bag is stored in a pitcher or jug.
A typical milk bag contains approximately of milk in South America, Iran, Israel, and conti ...
s are starting to appear in supermarkets, but have not yet proved popular. Most UHT-milk is packed in 1 or 2 liter paper containers with a sealed plastic spout.
;Brazil
: Used to be sold in cooled 1-liter bags, just like in South Africa. Today the most common form is 1-liter aseptic cartons containing UHT skimmed, semi-skimmed or whole milk, although the plastic bags are still in use for pasteurized milk. Higher grades of pasteurized milk can be found in cartons or plastic bottles. Sizes other than 1-liter are rare.
;Canada
: 1.33 liter plastic bags (sold as 4 liters in 3 bags) are widely available in some areas (especially the
Maritimes
The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Ca ...
, Ontario and
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
), although the 4 liter plastic jug has supplanted them in western Canada. Other common packaging sizes are 2 liter, 1 liter, 500 mL, and 250 mL cartons, as well as 4 liter, 1 liter, 250 mL aseptic cartons and 500 mL plastic jugs.
;Chile
: Distributed most commonly in
aseptic
Asepsis is the state of being free from disease-causing micro-organisms (such as pathogenic bacteria, viruses, pathogenic fungi, and parasites). There are two categories of asepsis: medical and surgical. The modern day notion of asepsis is deriv ...
cartons for up to 1 liter, but smaller, snack-sized cartons are also popular. The most common flavors, besides the natural presentation, are chocolate, strawberry and vanilla.
;China
: Sweetened milk is a drink popular with students of all ages and is often sold in small plastic bags complete with straw. Adults not wishing to drink at a banquet often drink milk served from cartons or
milk tea
Milk tea refers to several forms of beverage found in many cultures, consisting of some combination of tea and milk. The term milk tea is used for both hot and cold drinks that can be combined with various kinds of milks and a variety of spices. ...
.
;Colombia
:Sells milk in 1-liter plastic bags.
;Croatia, Bosnia and Herzegovina, Serbia, Montenegro
: UHT milk (''trajno mlijeko/trajno mleko/''трајно млеко) is sold in 500 mL and 1 L (sometimes also 200 mL) aseptic cartons. Non-UHT pasteurized milk (''svježe mlijeko/sveže mleko/''свеже млеко) is most commonly sold in 1 L and 1.5 L PET bottles, though in Serbia one can still find milk in plastic bags.
;Estonia
: Commonly sold in 1 L bags or 0.33 L, 0.5 L, 1 L or 1.5 L cartons.
; Parts of Europe
: Sizes of 500 mL, 1 liter (the most common), 1.5 liters, 2 liters and 3 liters are commonplace.
;Finland
: Commonly sold in 1 L or 1.5 L cartons, in some places also in 2 dl and 5 dl cartons.
;Germany
: Commonly sold in 1-liter cartons. Sale in 1-liter plastic bags (common in the 1980s) is now rare.
;Hong Kong
: Milk is sold in glass bottles (220 mL), cartons (236 mL and 1 L), plastic jugs (2 liters) and aseptic cartons (250 mL).
;India
: Commonly sold in 500 mL plastic bags and in bottles in some parts like in the
West
West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sunset, Sun sets on the Earth.
Etymology
The word "west" is a Germanic languages, German ...
. It is still customary to serve the milk boiled, despite pasteurization. Milk is often buffalo milk. Flavored milk is sold in most convenience stores in waxed cardboard containers. Convenience stores also sell many varieties of milk (such as flavored and ultra-pasteurized) in various sizes, usually in aseptic cartons.
;Indonesia
: Usually sold in 1-liter cartons, but smaller, snack-sized cartons are available.
;Italy
: Commonly sold in 1-liter cartons or bottles and less commonly in 0.5 or 0.25-liter cartons. Whole milk, semi-skimmed milk, skimmed, lactose-free, and flavored (usually in small packages) milk is available. Milk is sold fresh or UHT. Goat's milk is also available in small amounts. UHT semi-skimmed milk is the most sold, but cafés use almost exclusively fresh whole milk.
;Japan
: Commonly sold in 1-liter waxed paperboard cartons. In most city centers there is also
home delivery
Delivery is the process of transporting goods from a source location to a predefined destination. Cargo (physical goods) is primarily delivered via roads and railroads on land, shipping lanes on the sea, and airline networks in the air. Cer ...
of milk in glass jugs. As seen in China, sweetened and flavored milk drinks are commonly seen in
vending machine
A vending machine is an automated machine that provides items such as snacks, beverages, cigarettes, and lottery tickets to consumers after cash, a credit card, or other forms of payment are inserted into the machine or otherwise made. The fir ...
s.
;Kenya
:Milk in Kenya is mostly sold in plastic-coated aseptic paper cartons supplied in 300 mL, 500 mL or 1 liter volumes. In rural areas, milk is stored in plastic bottles or gourds. The standard unit of measuring milk quantity in
Kenya
)
, national_anthem = "Ee Mungu Nguvu Yetu"()
, image_map =
, map_caption =
, image_map2 =
, capital = Nairobi
, coordinates =
, largest_city = Nairobi
, ...
is a liter.
;Pakistan
: Milk is supplied in 500 mL plastic bags and carried in jugs from rural to cities for selling
;Philippines
: Milk is supplied in 1000 mL plastic bottles and delivered from factories to cities for selling.
;Poland
: UHT milk is mostly sold in aseptic cartons (500 mL, 1 L, 2 L), and non-UHT in 1 L plastic bags or plastic bottles. Milk, UHT is commonly boiled, despite being pasteurized.
;South Africa
: Commonly sold in 1-liter bags. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.
;South Korea
: Sold in cartons (180 mL, 200 mL, 500 mL 900 mL, 1 L, 1.8 L, 2.3 L), plastic jugs (1 L and 1.8 L), aseptic cartons (180 mL and 200 mL) and plastic bags (1 L).
;Sweden
: Commonly sold in 0.3 L, 1 L or 1.5 L cartons and sometimes as plastic or glass milk bottles.
;Turkey
: Commonly sold in 500 mL or 1L cartons or special plastic bottles. UHT milk is more popular. Milkmen also serve in smaller towns and villages.
;United Kingdom
: Most stores stock
imperial
Imperial is that which relates to an empire, emperor, or imperialism.
Imperial or The Imperial may also refer to:
Places
United States
* Imperial, California
* Imperial, Missouri
* Imperial, Nebraska
* Imperial, Pennsylvania
* Imperial, Texa ...
sizes: 1 pint (568 mL), 2 pints (1.136 L), 4 pints (2.273 L), 6 pints (3.408 L) or a combination including both metric and imperial sizes. Glass milk bottles delivered to the doorstep by the milkman are typically pint-sized and are returned empty by the householder for repeated
reuse
Reuse is the action or practice of using an item, whether for its original purpose (conventional reuse) or to fulfill a different function ( creative reuse or repurposing). It should be distinguished from recycling, which is the breaking down of u ...
. Milk is sold at supermarkets in either aseptic cartons or HDPE bottles. Supermarkets have also now begun to introduce milk in bags, to be poured from a proprietary jug and nozzle.
;United States
: Commonly sold in
gallon
The gallon is a unit of volume in imperial units and United States customary units. Three different versions are in current use:
*the imperial gallon (imp gal), defined as , which is or was used in the United Kingdom, Ireland, Canada, Austral ...
(3.78 L), half-gallon (1.89 L) and
quart
The quart (symbol: qt) is an English unit of volume equal to a quarter gallon. Three kinds of quarts are currently used: the liquid quart and dry quart of the US customary system and the of the British imperial system. All are roughly equal ...
(0.94 L) containers of natural-colored HDPE resin, or, for sizes less than one gallon, cartons of waxed paperboard. Bottles made of opaque
PET
A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...
are also becoming commonplace for smaller, particularly metric, sizes such as one liter. The US single-serving size is usually the half-pint (about 240 mL). Less frequently, dairies deliver milk directly to consumers, from coolers filled with glass bottles which are typically half-gallon sized and returned for reuse. Some convenience store chains in the United States (such as
Kwik Trip
Kwik Trip is a chain of convenience stores founded in 1965 with locations throughout Michigan, Minnesota, South Dakota, and Wisconsin under the name Kwik Trip, and in Illinois and Iowa under the name Kwik Star (to avoid confusion with QuikTri ...
in the
Midwest
The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of ...
warehouse club
A warehouse club (or wholesale club) is a retail store, usually selling a wide variety of merchandise, in which customers may buy large, wholesale quantities of the store's products, which makes these clubs attractive to both bargain hunters ...
s such as
Costco
Costco Wholesale Corporation (doing business as Costco Wholesale and also known simply as Costco) is an American multinational corporation which operates a chain of membership-only big-box retail stores (warehouse club). As of 2022, Costco i ...
and
Sam's Club
Sam's West, Inc. (doing business as Sam's Club) is an American chain of membership-only retail warehouse clubs owned and operated by Walmart Inc., founded in 1983 and named after Walmart founder Sam Walton as Sam’s Wholesale Club. , Sam's Cl ...
, along with some
Walmart
Walmart Inc. (; formerly Wal-Mart Stores, Inc.) is an American multinational retail corporation that operates a chain of hypermarkets (also called supercenters), discount department stores, and grocery stores from the United States, headquarter ...
stores.
;Uruguay
: Pasteurized milk is commonly sold in 1-liter bags and ultra-pasteurized milk is sold in cardboard boxes called
Tetra Brik
Tetra Brik is a brand name for a carton package produced by the Swedish packaging company Tetra Pak. Its shape is cubic or cuboid, and it is available with or without various different caps. The Tetra Brik is the best-known and most sold package ...
s. Non-pasteurized milk is forbidden. Until the 1960s no treatment was applied; milk was sold in bottles. , plastic jugs used for pouring the bags, or "sachets", are in common use.
Practically everywhere,
condensed milk
Condensed milk is cow's milk from which water has been removed (roughly 60% of it). It is most often found with sugar added, in the form of ''sweetened condensed milk'' (SCM), to the extent that the terms "condensed milk" and "sweetened condens ...
and evaporated milk are distributed in metal cans, 250 and 125 mL paper containers and 100 and 200 mL squeeze tubes, and
powdered milk
Powdered milk, also called milk powder, dried milk, or dry milk, is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and do ...
(skim and whole) is distributed in boxes or bags.
Spoilage and fermented milk products
When
raw milk
Raw milk or unpasteurized milk is milk that has not been pasteurized, a process of heating liquid foods to kill pathogens for safe consumption and extending the shelf life.
Proponents of raw milk have asserted numerous supposed benefits to consu ...
is left standing for a while, it turns "
sour
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...
". This is the result of
fermentation
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
, where
lactic acid bacteria
Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacte ...
ferment the
lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix '' - ...
in the milk into
lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...
. Prolonged fermentation may render the milk unpleasant to consume. This fermentation process is exploited by the introduction of bacterial cultures (e.g. ''
Lactobacilli
The ''Lactobacillaceae'' are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the ''Lactobacillaceae,'' the pathway used for hexose fermentati ...
sp.,
Streptococcus
''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...
sp.,
Leuconostoc
''Leuconostoc'' is a genus of gram-positive bacteria, placed within the family of Lactobacillaceae. They are generally ovoid cocci often forming chains. ''Leuconostoc'' spp. are intrinsically resistant to vancomycin and are catalase-negative (w ...
sp.'', etc.) to produce a variety of
fermented milk products
Fermented milk products or fermented dairy products, also known as cultured dairy foods, cultured dairy products, or cultured milk products, are dairy foods that have been fermented with lactic acid bacteria such as ''Lactobacillus'', ''Lactococcu ...
. The reduced pH from lactic acid accumulation denatures proteins and causes the milk to undergo a variety of different transformations in appearance and texture, ranging from an aggregate to smooth consistency. Some of these products include
sour cream
Sour cream (in North American English, Australian English and New Zealand English) or soured cream (British English) is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, wh ...
,
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
, cheese,
buttermilk
Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in western countries is not made with cultured cream but uncultured sweet cream, most mod ...
,
viili
Viili (Finnish) is a mesophilic fermented milk product found in the Nordic countries, particularly Finland. Viili is similar to yoghurt or kefir, but when left unmixed, its texture is malleable, or "long". The metabolism of the bacteria used in ...
,
kefir
Kefir ( ; also spelled as kephir or kefier; ; ; ) is a fermented milk drink similar to a thin yogurt or ayran that is made from kefir grains, a specific type of mesophilic symbiotic culture. The drink originated in the North Caucasus, in pa ...
, and
kumis
''Kumis'' (also spelled ''kumiss'' or ''koumiss'' or ''kumys'', see other transliterations and cognate words below under terminology and etymology – otk, airag kk, қымыз, ''qymyz'') mn, айраг, ''ääryg'') is a fermented dairy p ...
. ''See
Dairy product
Dairy products or milk products, also known as lacticinia, are food products made from (or containing) milk. The most common dairy animals are cow, water buffalo, nanny goat, and ewe. Dairy products include common grocery store food items in th ...
'' for more information.
Pasteurization
Pasteurization or pasteurisation is a process of food preservation in which packaged and non-packaged foods (such as milk and fruit juices) are treated with mild heat, usually to less than , to eliminate pathogens and extend shelf life.
The ...
of cow's milk initially destroys any potential pathogens and increases the shelf life, but eventually results in spoilage that makes it unsuitable for consumption. This causes it to assume an
unpleasant odor
An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense ...
, and the milk is deemed non-consumable due to unpleasant taste and an increased risk of food poisoning. In raw milk, the presence of lactic acid-producing bacteria, under suitable conditions, ferments the lactose present to lactic acid. The increasing
acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
ity in turn prevents the growth of other organisms, or slows their growth significantly. During pasteurization, however, these lactic acid bacteria are mostly destroyed.
In order to prevent spoilage, milk can be kept
refrigerated
The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...
and stored between in
bulk tank {{no footnotes, date=June 2013
In dairy farming a bulk milk cooling tank is a large storage tank for cooling and holding milk at a cold temperature until it can be picked up by a milk hauler.
The bulk milk cooling tank is an important piece of dai ...
s. Most milk is pasteurized by heating briefly and then refrigerated to allow transport from
factory farms
Intensive animal farming or industrial livestock production, also known by its opponents as factory farming and macro-farms, is a type of intensive agriculture, specifically an approach to animal husbandry designed to maximize production, while ...
to local markets. The spoilage of milk can be forestalled by using ultra-high temperature (
UHT
Ultra-high temperature processing (UHT), ultra-heat treatment, or ultra-pasteurization is a food processing technology that sterilizes liquid food by heating it above – the temperature required to kill bacterial endospores – for 2 ...
) treatment. Milk so treated can be stored unrefrigerated for several months until opened but has a characteristic "cooked" taste.
Condensed milk
Condensed milk is cow's milk from which water has been removed (roughly 60% of it). It is most often found with sugar added, in the form of ''sweetened condensed milk'' (SCM), to the extent that the terms "condensed milk" and "sweetened condens ...
, made by removing most of the water, can be stored in cans for many years, unrefrigerated, as can
evaporated milk
Evaporated milk, known in some countries as "unsweetened condensed milk", is a shelf-stable canned cow’s milk product where about 60% of the water has been removed from fresh milk. It differs from sweetened condensed milk, which contains adde ...
.
Powdered milk
The most durable form of milk is
powdered milk
Powdered milk, also called milk powder, dried milk, or dry milk, is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and do ...
, which is produced from milk by removing almost all water. The moisture content is usually less than 5% in both drum- and spray-dried powdered milk.
Freezing of milk can cause fat globule aggregation upon thawing, resulting in milky layers and butterfat lumps. These can be dispersed again by warming and stirring the milk.p. 58 /ref> It can change the taste by destruction of milk-fat globule membranes, releasing oxidized flavors.
Use in other food products
Milk is used to make
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
, cheese,
ice milk
Ice milk, or iced milk, is a frozen dessert with less than 10 percent milk fat and the same sweetener content as ice cream. Ice milk is sometimes priced lower than ice cream.
A 1994 change in United States Food and Drug Administration rules all ...
,
pudding
Pudding is a type of food. It can be either a dessert or a savoury (salty or spicy) dish served as part of the main meal.
In the United States, ''pudding'' means a sweet, milk-based dessert similar in consistency to egg-based custards, ins ...
,
hot chocolate
Hot chocolate, also known as hot cocoa or drinking chocolate, is a heated drink consisting of shaved chocolate, melted chocolate or cocoa powder, heated milk or water, and usually a sweetener like whipped cream or marshmallows. Hot chocolate ...
and french toast, among many other products. Milk is often added to dry
breakfast cereal
Cereal, formally termed breakfast cereal (and further categorized as cold cereal or warm cereal), is a traditional breakfast food made from processed cereal grains. It is traditionally eaten as part of breakfast, or a snack food, primarily in ...
,
porridge
Porridge is a food made by heating or boiling ground, crushed or chopped starchy plants, typically grain, in milk or water. It is often cooked or served with added flavourings such as sugar, honey, (dried) fruit or syrup to make a sweet cereal, ...
and
granola
Granola is a breakfast and snack food consisting of rolled oats, nuts, honey or other sweeteners such as brown sugar, and sometimes puffed rice, that is usually baked until crisp, toasted and golden brown. The mixture is stirred while baking ...
. Milk is mixed with ice cream and flavored syrups in a blender to make
milkshake
A milkshake (sometimes simply called a shake) is a sweet beverage made by blending milk, ice cream, and flavorings or sweeteners such as butterscotch, caramel sauce, chocolate syrup, fruit syrup, or whole fruit into a thick, sweet, cold mixture ...
s. Milk is often served in coffee and tea. Frothy steamed milk is used to prepare
espresso
Espresso (, ) is a coffee-brewing method of Italian origin, in which a small amount of nearly boiling water (about ) is forced under of pressure through finely-ground coffee beans. Espresso can be made with a wide variety of coffee beans and ...
-based drinks such as
cafe latte
Caffè latte (), often shortened to just latte () in English, is a coffee beverage of Italian origin made with espresso and steamed milk. Variants include the chocolate-flavored mocha or replacing the coffee with another beverage base such as ma ...
.
In language and culture
The importance of milk in human culture is attested to by the numerous expressions embedded in our languages, for example, "the milk of human kindness", the expression "there's no use crying over spilt milk" (which means don't "be unhappy about what cannot be undone"), "don't milk the ram" (this means "to do or attempt something futile") and "Why buy a cow when you can get milk for free?" (which means "why pay for something that you can get for free otherwise").
In
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
, the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...
was formed after the
trickster
In mythology and the study of folklore and religion, a trickster is a character in a story (god, goddess, spirit, human or anthropomorphisation) who exhibits a great degree of intellect or secret knowledge and uses it to play tricks or otherwi ...
god
Hermes
Hermes (; grc-gre, Ἑρμῆς) is an Olympian deity in ancient Greek religion and mythology. Hermes is considered the herald of the gods. He is also considered the protector of human heralds, travellers, thieves, merchants, and orato ...
suckled the infant
Heracles
Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptive ...
at the breast of
Hera
In ancient Greek religion, Hera (; grc-gre, Ἥρα, Hḗrā; grc, Ἥρη, Hḗrē, label=none in Ionic and Homeric Greek) is the goddess of marriage, women and family, and the protector of women during childbirth. In Greek mythology, she ...
, the queen of the gods, while she was asleep. When Hera awoke, she tore Heracles away from her breast and splattered her breast milk across the heavens. In another version of the story,
Athena
Athena or Athene, often given the epithet Pallas, is an ancient Greek goddess associated with wisdom, warfare, and handicraft who was later syncretized with the Roman goddess Minerva. Athena was regarded as the patron and protectress of ...
, the patron goddess of heroes, tricked Hera into suckling Heracles voluntarily, but he bit her nipple so hard that she flung him away, spraying milk everywhere.
In many African and Asian countries, butter is traditionally made from fermented milk rather than cream. It can take several hours of churning to produce workable butter grains from fermented milk.
Holy books have also mentioned milk. The Bible contains references to the "
Land of Milk and Honey
''Land of Milk and Honey'' () is a 1971 French documentary film directed by Pierre Étaix. It is about the state of the French society in the wake of the May 1968 events. The film was released in France on February 24, 1971.
Reception
The film was ...
" as a metaphor for the bounty of the Promised Land. In the
Qur'an
The Quran (, ; Standard Arabic: , Quranic Arabic: , , 'the recitation'), also romanized Qur'an or Koran, is the central religious text of Islam, believed by Muslims to be a revelation from God. It is organized in 114 chapters (pl.: , sing. ...
, there is a request to wonder on milk as follows: "And surely in the livestock there is a lesson for you, We give you to drink of that which is in their bellies from the midst of digested food and blood, pure milk palatable for the drinkers" (16-The Honeybee, 66). The
Ramadan
, type = islam
, longtype = Religious
, image = Ramadan montage.jpg
, caption=From top, left to right: A crescent moon over Sarıçam, Turkey, marking the beginning of the Islamic month of Ramadan. Ramadan Quran reading in Bandar Torkaman, Iran. ...
fast is traditionally broken with a glass of milk and dates.
Abhisheka
Abhisheka () means "bathing of the divinity to whom worship is offered." It is a religious rite or method of prayer in which a devotee pours a liquid offering on an image or murti of a God or Goddess. Abhisheka is common to Indian religions su ...
is conducted by
Hindu
Hindus (; ) are people who religiously adhere to Hinduism.Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pages 35–37 Historically, the term has also been used as a geographical, cultural, and later religious identifier for ...
and
Jain
Jainism ( ), also known as Jain Dharma, is an Indian religion. Jainism traces its spiritual ideas and history through the succession of twenty-four tirthankaras (supreme preachers of ''Dharma''), with the first in the current time cycle being ...
priests, by pouring libations on the idol of a deity being worshipped, amidst the chanting of
mantra
A mantra (Pali: ''manta'') or mantram (मन्त्रम्) is a sacred utterance, a numinous sound, a syllable, word or phonemes, or group of words in Sanskrit, Pali and other languages believed by practitioners to have religious, ma ...
s. Usually offerings such as milk,
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
,
ghee
Ghee is a type of clarified butter, originating from India. It is commonly used in India for cooking, as a traditional medicine, and for religious rituals.
Description
Ghee is typically prepared by simmering butter, which is churned from c ...
,
honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
may be poured among other offerings depending on the type of abhishekam being performed.
A milksop is an "effeminate spiritless man," an expression which is attested to in the late 14th century.
Milk toast
Milk toast is a breakfast dish consisting of toasted bread in warm milk, typically with sugar and butter."An Alphabet For Gourmets" by Mary Francis Kennedy Fisher, MacMillan Salt, pepper, paprika, cinnamon, cocoa, raisins or other ingredient ...
is a dish consisting of milk and toast. Its soft blandness served as inspiration for the name of the timid and ineffectual
comic strip
A comic strip is a sequence of drawings, often cartoons, arranged in interrelated panels to display brief humor or form a narrative, often serialized, with text in balloons and captions. Traditionally, throughout the 20th and into the 21st ...
character
Caspar Milquetoast
Caspar Milquetoast is a comic strip character created by H. T. Webster for his cartoon series ''The Timid Soul''. Webster described Caspar Milquetoast as "the man who speaks softly and gets hit with a big stick". The character's name is deriv ...
, drawn by
H. T. Webster
Harold Tucker Webster (September 21, 1885 – September 22, 1952) was an American cartoonist known for '' The Timid Soul'', ''Bridge'', ''Life's Darkest Moments'' and others in his syndicated series which ran from the 1920s into the 1950s. Because ...
from 1924 to 1952. Thus, the term "milquetoast" entered the language as the label for a timid, shrinking, apologetic person. Milk toast also appeared in Disney's '' Follow Me Boys'' as an undesirable breakfast for the aging main character Lem Siddons.
To "milk" someone, in the vernacular of many English-speaking countries, is to take advantage of the person, by analogy to the way a farmer "milks" a cow and takes its milk. The word "milk" has had many slang meanings over time. In the 19th century, milk was used to describe a cheap and very poisonous alcoholic drink made from
methylated spirits
Denatured alcohol (also called methylated spirits in Australia, Canada, Ireland, New Zealand, South Africa, and the United Kingdom; wood spirit; and denatured rectified spirit) is ethanol that has additives to make it poisonous, bad-tasting, fou ...
(methanol) mixed with water. The word was also used to mean defraud, to be idle, to intercept telegrams addressed to someone else, and a weakling or "milksop." In the mid-1930s, the word was used in Australia to refer to siphoning gas from a car.
Non-culinary uses
Besides serving as a beverage or source of food, milk has been described as used by farmers and gardeners as an organic
fungicide
Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...
and fertilizer, however, its effectiveness is debated. Diluted milk solutions have been demonstrated to provide an effective method of preventing powdery mildew on grape vines, while showing it is unlikely to harm the plant.
Milk paint
Milk paint is a nontoxic milk-based paint. It can be made from milk and lime, generally with pigments added for color. In other recipes, borax is mixed with milk's casein protein in order to activate the casein and as a preservative.
Milk paint ...
is a
nontoxic
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...
water-based
paint
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...
. It can be made from milk and
lime
Lime commonly refers to:
* Lime (fruit), a green citrus fruit
* Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide
* Lime (color), a color between yellow and green
Lime may also refer to:
Botany ...
, generally with
pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...
s added for color. In other recipes,
borax
Borax is a salt (ionic compound), a hydrated borate of sodium, with chemical formula often written . It is a colorless crystalline solid, that dissolves in water to make a basic solution. It is commonly available in powder or granular form, ...
is mixed with milk's casein protein in order to activate the
casein
Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of ...
and as a preservative.
Milk has been used for centuries as a hair and skin treatment.
Hairstylist Richard Marin states that some women rinse their hair with milk to add a shiny appearance to their hair. Cosmetic chemist Ginger King states that milk can "help exfoliate and remove debris rom skinand make hair softer. Hairstylist Danny Jelaca states that milk's keratin proteins may "add weight to the hair". Some commercial hair products contain milk.
A
milk bath
A milk bath is a Bathing, bath taken in milk instead of water. Often other scents such as honey, rose, Asteraceae, daisies and essential oils are added. Milk baths use lactic acid, an alpha hydroxy acid, to dissolve the proteins which hold together ...
is a bath taken in milk rather than just water. Often additives such as oatmeal,
honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
, and scents such as
rose
A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can be ...
essential oils
An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...
are mixed in. Milk baths use
lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...
, an
alpha hydroxy acid
α-Hydroxy acids, or alpha hydroxy acids (AHAs), are a class of chemical compounds that consist of a carboxylic acid with a hydroxyl group substituent on the adjacent (alpha) carbon. Prominent examples are glycolic acid, lactic acid, mandelic aci ...
, to dissolve the proteins which hold together dead skin cells.
Interspecies milk consumption
The consumption of milk between species is not unique to humans. Although the occurrence of this utilization is not vastly documented, interspecies consumption of milk has been observed among the
red-billed oxpecker
The red-billed oxpecker (''Buphagus erythrorynchus'') is a passerine bird in the oxpecker family, Buphagidae. It is native to the savannah of sub- Saharan Africa, from the Central African Republic east to South Sudan and south to northern and eas ...
—a bird that can perch on the
udders
An udder is an organ formed of two or four mammary glands on the females of dairy animals and ruminants such as cattle, goats, and sheep. An udder is equivalent to the breast in primates and elephantine pachyderms. The udder is a single mass ha ...
of an
impala
The impala or rooibok (''Aepyceros melampus'') is a medium-sized antelope found in eastern and southern Africa. The only extant member of the genus '' Aepyceros'' and tribe Aepycerotini, it was first described to European audiences by Germa ...
and suck its milk.
Seagulls
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, ...
Skuas
The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called jae ...
elephant seals
Elephant seals are very large, oceangoing earless seals in the genus ''Mirounga''. Both species, the northern elephant seal (''M. angustirostris'') and the southern elephant seal (''M. leonina''), were hunted to the brink of extinction for oil ...
’ teats.
Jewish/Kosher milk
Chalav Yisrael
''Chalav Yisrael'', also pronounced ''cholov Yisroel'', refers to kosher milk whose milking was observed by an observant Jew. The ''halakha'' of ''chalav Yisrael'', which originates in the Mishnah and Talmud, was instituted to ensure that no non ...
* Dillon, John J. ''Seven decades of milk,: A history of New York's dairy industry'' (1941)
* Innis, Harold A. ''The dairy industry in Canada'' (1937 online * Kardashian, Kirk. ''Milk Money: Cash, Cows, and the Death of the American Dairy Farm'' (2012)
* Kurlansky, Mark. ''Milk: A 10,000-Year History'' (2019); also published as ''Milk!: A 10,000-Year Food Fracas'' (2019)
*
*
*
* Smith-Howard, Kendra. ''Pure and Modern Milk: An Environmental History Since 1900.'' (Oxford University Press; 2013).
* Valenze, Deborah. ''Milk: A Local and Global History'' (Yale University Press, 2011) 368 pp.
* Wiley, Andrea. ''Re-imagining Milk: Cultural and Biological Perspectives'' (Routledge 2010) (Series for Creative Teaching and Learning in Anthropology)