Meat Hous At Davenport Downs 1925
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Meat is animal flesh that is eaten as
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 ...
. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in 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 ...
allowed the
domestication of animals The domestication of animals is the mutual relationship between non-human animals and the humans who have influence on their care and reproduction. Charles Darwin recognized a small number of traits that made domesticated species different from t ...
such as chickens, sheep, rabbits, pigs, and cattle. This eventually led to their use in meat production on an industrial scale in
slaughterhouse A slaughterhouse, also called abattoir (), is a facility where animals are slaughtered to provide food. Slaughterhouses supply meat, which then becomes the responsibility of a packaging facility. Slaughterhouses that produce meat that is no ...
s. Meat is mainly composed of water, protein, and fat. It is edible raw but is normally eaten after it has been cooked and seasoned or processed in a variety of ways. Unprocessed meat will spoil or rot within hours or days as a result of infection with, and decomposition by, bacteria and fungi. Meat is important to the
food industry The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditiona ...
, economies, and cultures around the world. There are nonetheless people who choose to not eat meat ( vegetarians) or any animal products ( vegans), for reasons such as taste preferences, ethics, environmental concerns, health concerns or religious dietary rules.


Terminology

The word ''meat'' comes from the
Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...
word , which referred to food in general. The term is related to in Danish, in
Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...
and Norwegian, and in Icelandic and Faroese, which also mean 'food'. The word also exists in Old Frisian (and to a lesser extent, modern West Frisian) to denote important food, differentiating it from (sweets) and (animal feed). Most often, ''meat'' refers to
skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
and associated fat and other tissues, but it may also describe other edible tissues such as offal. ''Meat'' is sometimes also used in a more restrictive sense to mean the flesh 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 ...
ian species (pigs, cattle, sheep, goats, etc.) raised and prepared for human consumption, to the exclusion of fish, other
seafood Seafood is any form of sea life regarded as food by humans, prominently including fish and shellfish. Shellfish include various species of molluscs (e.g. bivalve molluscs such as clams, oysters and mussels, and cephalopods such as octopus an ...
, insects, poultry, or other animals. In the context of food, ''meat'' can also refer to "the edible part of something as distinguished from its covering (such as a husk or shell)", for example, ''coconut meat''. In English, there are also specialized terms for the meat of particular animals. These terms originated with the
Norman conquest of England The Norman Conquest (or the Conquest) was the 11th-century invasion and occupation of England by an army made up of thousands of Normans, Norman, Duchy of Brittany, Breton, County of Flanders, Flemish, and Kingdom of France, French troops, ...
in 1066: while the animals retained their English names, their meat as brought to the tables of the invaders was referred to them with the
Norman French Norman or Norman French (, french: Normand, Guernésiais: , Jèrriais: ) is a Romance language which can be classified as one of the Oïl languages along with French, Picard and Walloon. The name "Norman French" is sometimes used to descri ...
words for the respective animal. In time, these appellations came to be used by the entire population.


History


Hunting and farming

Paleontological evidence suggests that meat constituted a substantial proportion of the diet of the earliest humans. Early
hunter-gatherer 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, ...
s depended on the organized hunting of large animals such as
bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...
and deer. The domestication of animals, of which we have evidence dating back to the end of the last glacial period (c. 10,000 BCE), allowed the systematic production of meat and the breeding of animals with a view to improving meat production. Animals that are now principal sources of meat were domesticated in conjunction with the development of early civilizations: * Sheep, originating from western Asia, were domesticated with the help of dogs prior to the establishment of settled agriculture, likely as early as the 8th millennium BCE. Several breeds of sheep were established in ancient Mesopotamia and Egypt by 3500–3000 BCE. Today, more than 200 sheep-breeds exist. * Cattle were domesticated in Mesopotamia after settled agriculture was established about 5000 BCE, and several breeds were established by 2500 BCE. Modern domesticated cattle fall into the groups '' Bos taurus'' (European cattle) and ''
Bos taurus indicus The zebu (; ''Bos indicus'' or ''Bos taurus indicus''), sometimes known in the plural as indicine cattle or humped cattle, is a species or subspecies of domestic cattle originating in the Indian sub-continent. Zebu are characterised by a fatty ...
'' (zebu), both descended from the now-extinct
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 ...
. The breeding of beef cattle, cattle optimized for meat production as opposed to animals best suited for work or dairy purposes, began in the middle of the 18th century. * Domestic pigs, which are descended from wild boars, are known to have existed about 2500 BCE in modern-day Hungary and in Troy; earlier pottery from Tell es-Sultan (Jericho) and Egypt depicts wild pigs. Pork sausages and hams were of great commercial importance in
Greco-Roman The Greco-Roman civilization (; also Greco-Roman culture; spelled Graeco-Roman in the Commonwealth), as understood by modern scholars and writers, includes the geographical regions and countries that culturally—and so historically—were di ...
times. Pigs continue to be bred intensively as they are being optimized to produce meat best suited for specific meat products. * Goats are among the earliest animals domesticated by humans. The most recent genetic analysis confirms the archaeological evidence that the wild
bezoar ibex The bezoar ibex (''Capra aegagrus aegagrus'') is a wild goat subspecies that is native to the montane forested areas in the Caucasus and the Zagros Mountains. Characteristics The bezoar ibex, which weighs around 60kg (130lb) is known particu ...
of the Zagros Mountains is the likely original ancestor of probably all domestic goats today. Neolithic farmers began to herd wild goats primarily for easy access to milk and meat, as well as to their dung, which was used as fuel; and their bones, hair, and sinew were used for clothing, building, and tools.Hirst, K. Kris
"The History of the Domestication of Goats".
'' About.com''. Accessed August 18, 2008.
The earliest remnants of domesticated goats dating 10,000 years Before Present are found in Ganj Dareh in Iran. Goat remains have been found at archaeological sites in
Jericho Jericho ( ; ar, أريحا ; he, יְרִיחוֹ ) is a Palestinian city in the West Bank. It is located in the Jordan Valley, with the Jordan River to the east and Jerusalem to the west. It is the administrative seat of the Jericho Gove ...
,
Choga Mami Choga Mami is a Samarran settlement site in Diyala province in Eastern Iraq in the Mandali region. It shows the first canal irrigation in operation at about 6000 BCE. The site, about 70 miles northeast of Baghdad, has been dated to the late 6th m ...
, Djeitun, and Çayönü, dating the domestication of goats in Western Asia at between 8,000 and 9,000 years ago. Studies of DNA evidence suggests 10,000 years ago as the domestication date. * Chicken were domesticated around 6000 BC in Southeast Asia, according to genomic analysis, and spread to China and India 2000–3000 years later. Archaeological evidence supports domestic chickens in Southeast Asia well before 6000 BCE, China by 6000 BCE and India by 2000 BCE. Other animals are or have been raised or hunted for their flesh. The type of meat consumed varies much between different cultures, changes over time, depending on factors such as tradition and the availability of the animals. The amount and kind of meat consumed also varies by income, both between countries and within a given country. * Deer are hunted for their meat ( venison) in various regions. *
Horses 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 yea ...
are commonly eaten in France, Italy, Germany and Japan, among other countries. Horses and other large
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 such as reindeer were hunted during the late
Paleolithic The Paleolithic or Palaeolithic (), also called the Old Stone Age (from Greek: παλαιός ''palaios'', "old" and λίθος ''lithos'', "stone"), is a period in human prehistory that is distinguished by the original development of stone too ...
in western Europe. *
Dogs The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...
are consumed in China, South Korea and Vietnam. Dogs are also occasionally eaten in the Arctic regions. Historically, dog meat has been consumed in various parts of the world, such as Hawaii, Japan, Switzerland and Mexico. *
Cats The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of t ...
are consumed in Southern China, Peru and sometimes also in
Northern Italy Northern Italy ( it, Italia settentrionale, it, Nord Italia, label=none, it, Alta Italia, label=none or just it, Nord, label=none) is a geographical and cultural region in the northern part of Italy. It consists of eight administrative regions ...
. * Guinea pigs are raised for their flesh in the Andes. * Whales and dolphins are hunted, partly for their flesh, in Japan, Alaska, Siberia, Canada, the Faroe Islands, Greenland, Iceland, Saint Vincent and the Grenadines and by two small communities in Indonesia. Modern agriculture employs a number of techniques, such as
progeny testing Progeny Testing is a test of the value for selective breeding of an individual's genotype by looking at the progeny produced by different matings. Progeny Testing It is used in the breeding of both plants and animals, but is most commercially i ...
, to speed
artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...
by breeding animals to rapidly acquire the qualities desired by meat producers. For instance, in the wake of well-publicised health concerns associated with
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 ...
s in the 1980s, the fat content of United Kingdom beef, pork and lamb fell from 20–26 percent to 4–8 percent within a few decades, due to both selective breeding for leanness and changed methods of butchery. Methods of
genetic engineering 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 ...
aimed at improving the meat production qualities of animals are now also becoming available. Even though it is a very old industry, meat production continues to be shaped strongly by the evolving demands of customers. The trend towards selling meat in pre-packaged cuts has increased the demand for larger breeds of cattle, which are better suited to producing such cuts. Even more animals not previously exploited for their meat are now being farmed, especially the more agile and mobile species, whose muscles tend to be developed better than those of cattle, sheep or pigs. Examples are the various
antelope The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia. Antelope comprise a wastebasket taxon defined as any of numerous Old World grazing and browsing hoofed mammals ...
species, the zebra, water buffalo and
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 ...
, as well as non-mammals, such as the
crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
, emu and ostrich. Another important trend in contemporary meat production is organic farming which, while providing no organoleptic benefit to meat so produced, meets an increasing demand for organic meat.


Culture

For most of human history, meat was a largely unquestioned part of the human diet. Only in the 20th century did it begin to become a topic of discourse and contention in society, politics and wider culture.


Consumption

Meat consumption varies worldwide, depending on cultural or religious preferences, as well as economic conditions. Vegetarians and vegans choose not to eat meat because of taste preferences, ethical, economic, environmental, religious, or health concerns that are associated with meat production and consumption. According to the analysis of the FAO, the overall consumption for white meat between 1990 and 2009 has dramatically increased. Poultry meat has increased by 76.6% per kilo per capita and pig meat by 19.7%. Bovine meat has decreased from per capita in 1990 to per capita in 2009. Overall, diets that include meat are the most common worldwide according to the results of a 2018 Ipsos MORI study of 16–64 years olds in 28 countries. Ipsos states "An omnivorous diet is the most common diet globally, with non-meat diets (which can include fish) followed by over a tenth of the global population." Approximately 87% of people include meat in their diet in some frequency. 73% of meat eaters included it in their diet regularly and 14% consumed meat only occasionally or infrequently. Estimates of the non-meat diets were also broken down. About 3% of people followed vegan diets, where consumption of meat, eggs, and dairy are abstained from. About 5% of people followed vegetarian diets, where consumption of meat is abstained from, but egg and/or dairy consumption is not strictly restricted. About 3% of people followed pescetarian diets, where consumption of the meat of land animals is abstained from, fish meat and other seafood is consumed, and egg and/or dairy consumption may or may not be strictly restricted.


History

A bioarchaeological (specifically,
isotopic analysis Isotope analysis is the identification of isotopic signature, abundance of certain stable isotopes of chemical elements within organic and inorganic compounds. Isotopic analysis can be used to understand the flow of energy through a food web, ...
) study of early medieval England found, based on the funerary record, that high-meat protein diets were extremely rare, and that (contrary to previously held assumptions) elites did not consume more meat than non-elites, and men did not consume more meat than women. In the nineteenth century meat consumption in Britain was the highest in Europe, exceeded only by that in British colonies. In the 1830s consumption per head in Britain was about 75 pounds a year, rising to 130 pounds in 1912. In 1904 laborers were found to consume 87 pounds a year while aristocrats ate 300 pounds. There were estimated to be 43,000 meat purveyor establishments in Britain in 1910, with "possibly more money invested in the meat industry than in any other British business" except the finance industry. The US was a meat importing country by 1926. Truncated lifespan as a result of intensive breeding allowed more meat to be produced from fewer animals. The world cattle population was about 600 million in 1929, with 700 million sheep and goats and 300 million pigs. According to a study, the average lifespan of livestock pigs is ~2 years (7% of " maximum expected lifespan"). For dairy cattle the lifespan is ~5 years (27%).


Animal growth and development

Agricultural science Agricultural science (or agriscience for short) is a broad multidisciplinary field of biology that encompasses the parts of exact, natural, economic and social sciences that are used in the practice and understanding of agriculture. Profession ...
has identified several factors bearing on the growth and development of meat in animals.


Genetics

Several economically important traits in meat animals are heritable to some degree (see the adjacent table) and can thus be selected for by animal breeding. In cattle, certain growth features are controlled by
recessive genes In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...
which have not so far been controlled, complicating breeding. One such trait is
dwarfism Dwarfism is a condition wherein an organism is exceptionally small, and mostly occurs in the animal kingdom. In humans, it is sometimes defined as an adult height of less than , regardless of sex; the average adult height among people with dw ...
; another is the doppelender or " double muscling" condition, which causes muscle hypertrophy and thereby increases the animal's commercial value. Genetic analysis continues to reveal the genetic mechanisms that control numerous aspects of the endocrine system and, through it, meat growth and quality.
Genetic engineering 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 ...
techniques can shorten breeding programs significantly because they allow for the identification and isolation of genes coding for desired traits, and for the reincorporation of these genes into the animal genome. To enable such manipulation, research is ongoing () to map the entire genome of sheep, cattle and pigs. Some research has already seen commercial application. For instance, a recombinant bacterium has been developed which improves the digestion of grass in the rumen of cattle, and some specific features of muscle fibres have been genetically altered. Experimental reproductive cloning of commercially important meat animals such as sheep, pig or cattle has been successful. Multiple asexual reproduction of animals bearing desirable traits is anticipated, although this is not yet practical on a commercial scale.


Environment

Heat regulation in livestock is of great economic significance, because mammals attempt to maintain a constant optimal body temperature. Low temperatures tend to prolong animal development and high temperatures tend to retard it. Depending on their size, body shape and insulation through tissue and fur, some animals have a relatively narrow zone of temperature tolerance and others (e.g. cattle) a broad one. Static
magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...
s, for reasons still unknown, also retard animal development.


Nutrition

The quality and quantity of usable meat depends on the animal's ''plane of nutrition'', i.e., whether it is over- or underfed. Scientists disagree about how exactly the plane of nutrition influences carcass composition. The composition of the diet, especially the amount of protein provided, is also an important factor regulating animal growth. Ruminants, which may digest cellulose, are better adapted to poor-quality diets, but their ruminal microorganisms degrade high-quality protein if supplied in excess. Because producing high-quality protein animal feed is expensive (see also '' Environmental impact'' below), several techniques are employed or experimented with to ensure maximum utilization of protein. These include the treatment of feed with formalin to protect amino acids during their passage through the rumen, the recycling of manure by feeding it back to cattle mixed with feed concentrates, or the partial conversion of petroleum hydrocarbons to protein through microbial action. In plant feed, environmental factors influence the availability of crucial
nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s or
micronutrient Micronutrients are nutrient, essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for exam ...
s, a lack or excess of which can cause a great many ailments. In Australia, for instance, where the soil contains limited phosphate, cattle are being fed additional phosphate to increase the efficiency of beef production. Also in Australia, cattle and sheep in certain areas were often found losing their appetite and dying in the midst of rich pasture; this was at length found to be a result of cobalt deficiency in the soil. Plant toxins are also a risk to grazing animals; for instance, sodium fluoroacetate, found in some African and Australian plants, kills by disrupting the cellular metabolism. Certain man-made pollutants such as
methylmercury Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula . It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a ...
and some
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
residues present a particular hazard due to their tendency to bioaccumulate in meat, potentially poisoning consumers.


Animal welfare

Livestock animals have shown relatively high intelligence which may raise animal ethics rationale for safeguarding their well-being. Pigs in particular are considered by some to be the smartest known domesticated animal in the world (e.g. more intelligent than pet dogs) which not only experience pain but also have notable depths, levels and/or variety/diversity of emotions (including boredom), cognition, intelligence, and/or sentience. Complications include that without or reduced meat production, many livestock animals may never live (see also:
natalism Natalism (also called pronatalism or the pro-birth position) is an ideology that promotes the reproduction of human life as the preeminent objective of being human. Compare: The term, as it relates to the belief itself, comes from the French wor ...
), and that their life (relative timespan of existence) is typically short – in the case of pigs ~7% of their "maximum expected lifespan".


Human intervention

Meat producers may seek to improve the fertility of female animals through the administration of gonadotrophic or ovulation-inducing hormones. In pig production, sow infertility is a common problem — possibly due to excessive fatness. No methods currently exist to augment the fertility of male animals. Artificial insemination is now routinely used to produce animals of the best possible genetic quality, and the efficiency of this method is improved through the administration of hormones that synchronize the ovulation cycles within groups of females. Growth hormones, particularly anabolic agents such as
steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...
s, are used in some countries to accelerate muscle growth in animals. This practice has given rise to the
beef hormone controversy The Beef Hormone Dispute is one of the most intractable agricultural controversies since the establishment of the World Trade Organization (WTO). It has sometimes been called the "beef war" in the media, similarly to the UK–EU Beef war over th ...
, an international trade dispute. It may also decrease the tenderness of meat, although research on this is inconclusive, and have other effects on the composition of the muscle flesh. Where
castration Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmaceut ...
is used to improve control over male animals, its side effects are also counteracted by the administration of hormones. Myostatin-based muscle hypertrophy has also been used.
Sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but t ...
s may be administered to animals to counteract stress factors and increase weight gain. The feeding of antibiotics to certain animals has been shown to improve growth rates also. This practice is particularly prevalent in the US, but has been banned in the EU, partly because it causes antimicrobial resistance in pathogenic microorganisms.


Biochemical composition

Numerous aspects of the biochemical composition of meat vary in complex ways depending on the species, breed, sex, age, plane of nutrition, training and exercise of the animal, as well as on the anatomical location of the musculature involved. Even between animals of the same litter and sex there are considerable differences in such parameters as the percentage of intramuscular fat.


Main constituents

Adult mammalian
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
flesh consists of roughly 75 percent water, 19 percent protein, 2.5 percent intramuscular fat, 1.2 percent carbohydrates and 2.3 percent other soluble non-protein substances. These include nitrogenous compounds, such as amino acids, and inorganic substances such as minerals. Muscle proteins are either soluble in water ( sarcoplasmic proteins, about 11.5 percent of total muscle mass) or in concentrated salt solutions ( myofibrillar proteins, about 5.5 percent of mass). There are several hundred sarcoplasmic proteins. Most of them – the glycolytic enzymes – are involved in the glycolytic pathway, i.e., the conversion of stored energy into muscle power. The two most abundant myofibrillar proteins,
myosin Myosins () are a superfamily of motor proteins best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. They are ATP-dependent and responsible for actin-based motility. The first myosin ...
and actin, are responsible for the muscle's overall structure. The remaining protein mass consists of
connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
(
collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
and
elastin Elastin is a protein that in humans is encoded by the ''ELN'' gene. Elastin is a key component of the extracellular matrix in gnathostomes (jawed vertebrates). It is highly elastic and present in connective tissue allowing many tissues in the bod ...
) as well as
organelle In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as organs are to the body, hence ''organelle,'' the ...
tissue. Fat in meat can be either adipose tissue, used by the animal to store energy and consisting of "true fats" ( esters of glycerol with fatty acids), or intramuscular fat, which contains considerable quantities of
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 and of unsaponifiable constituents such as cholesterol.


Red and white

Meat can be broadly classified as "red" or "white" depending on the concentration of
myoglobin Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobi ...
in muscle fibre. When myoglobin is exposed to oxygen, reddish oxymyoglobin develops, making myoglobin-rich meat appear red. The redness of meat depends on species, animal age, and fibre type: Red meat contains more narrow muscle fibres that tend to operate over long periods without rest, while white meat contains more broad fibres that tend to work in short fast bursts. Generally, the meat of adult mammals such as cows, sheep, and
horses 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 yea ...
is considered red, while chicken and turkey breast meat is considered white.


Nutritional information

All
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
tissue is very high in protein, containing all of the essential amino acids, and in most cases is a good source of zinc, vitamin B12, selenium, phosphorus, niacin, vitamin B6, choline,
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 ...
and iron. Several forms of meat are also high in vitamin K. Muscle tissue is very low in carbohydrates and does not contain dietary fiber. While taste quality may vary between meats, the proteins, vitamins, and minerals available from meats are generally consistent. The fat content of meat can vary widely depending on the species and
breed A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slig ...
of animal, the way in which the animal was raised, including what it was fed, the
anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...
part of the body, and the methods of butchering and cooking. Wild animals such as deer are typically leaner than farm animals, leading those concerned about fat content to choose
game A game is a structured form of play (activity), play, usually undertaken for enjoyment, entertainment or fun, and sometimes used as an educational tool. Many games are also considered to be work (such as professional players of spectator s ...
such as venison. Decades of breeding meat animals for fatness is being reversed by consumer demand for meat with less fat. The fatty deposits that exist with the muscle fibers in meats soften meat when it is cooked and improve the flavor through chemical changes initiated through heat that allow the protein and fat molecules to interact. The fat, when cooked with meat, also makes the meat seem juicier. The nutritional contribution of the fat is mainly calories as opposed to protein. As fat content rises, the meat's contribution to nutrition declines. In addition, there is cholesterol associated with fat surrounding the meat. The cholesterol is a lipid associated with the kind of saturated fat found in meat. The increase in meat consumption after 1960 is associated with, though not definitively the cause of, significant imbalances of fat and cholesterol in the human diet. The table in this section compares the nutritional content of several types of meat. While each kind of meat has about the same content of protein and carbohydrates, there is a very wide range of fat content.


Production

Meat is produced by killing an animal and cutting flesh out of it. These procedures are called slaughter and butchery, respectively. There is ongoing research into producing meat ''in vitro''; that is, outside of animals.


Transport

Upon reaching a predetermined age or weight, livestock are usually transported ''en masse'' to the slaughterhouse. Depending on its length and circumstances, this may exert stress and injuries on the animals, and some may die ''en route''. Unnecessary stress in transport may adversely affect the quality of the meat. In particular, the muscles of stressed animals are low in water and
glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...
, and their pH fails to attain acidic values, all of which results in poor meat quality. Consequently, and also due to campaigning by
animal welfare Animal welfare is the well-being of non-human animals. Formal standards of animal welfare vary between contexts, but are debated mostly by animal welfare groups, legislators, and academics. Animal welfare science uses measures such as longevity ...
groups, laws and industry practices in several countries tend to become more restrictive with respect to the duration and other circumstances of livestock transports.


Slaughter

Animals are usually slaughtered by being first stunned and then exsanguinated (bled out). Death results from the one or the other procedure, depending on the methods employed. Stunning can be effected through asphyxiating the animals with carbon dioxide, shooting them with a gun or a captive bolt pistol, or shocking them with electric current. In most forms of ritual slaughter, stunning is not allowed. Draining as much blood as possible from the carcass is necessary because blood causes the meat to have an unappealing appearance and is a breeding ground for microorganisms. The exsanguination is accomplished by severing the
carotid artery Carotid artery may refer to: * Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery * External carotid artery, an artery on each side of t ...
and the jugular vein in cattle and sheep, and the anterior vena cava in pigs. The act of slaughtering animals for meat, or of raising or transporting animals for slaughter, may engender both psychological stress and physical trauma in the people involved. Additionally, slaughterhouse workers are exposed to noise of between 76 and 100 dB from the screams of animals being killed. 80 dB is the threshold at which the wearing of
ear protection Ear protection refers to devices used to protect the ear, either externally from elements such as cold, intrusion by water and other environmental conditions, debris. High levels of exposure to noise may result in noise-induced hearing loss N ...
is recommended.


Dressing and cutting

After exsanguination, the carcass is dressed; that is, the head, feet, hide (except hogs and some veal), excess fat, viscera and offal are removed, leaving only bones and edible muscle. Cattle and pig carcases, but not those of sheep, are then split in half along the mid ventral axis, and the carcase is cut into wholesale pieces. The dressing and cutting sequence, long a province of manual labor, is progressively being fully automated.


Conditioning

Under hygienic conditions and without other treatment, meat can be stored at above its freezing point (–1.5 °C) for about six weeks without spoilage, during which time it undergoes an aging process that increases its tenderness and flavor. During the first day after death,
glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH ...
continues until the accumulation of lactic acid causes the pH to reach about 5.5. The remaining
glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...
, about 18 g per kg, is believed to increase the water-holding capacity and tenderness of the flesh when cooked. '' Rigor mortis'' sets in a few hours after death as
ATP ATP may refer to: Companies and organizations * Association of Tennis Professionals, men's professional tennis governing body * American Technical Publishers, employee-owned publishing company * ', a Danish pension * Armenia Tree Project, non ...
is used up, causing actin and
myosin Myosins () are a superfamily of motor proteins best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. They are ATP-dependent and responsible for actin-based motility. The first myosin ...
to combine into rigid actomyosin and lowering the meat's water-holding capacity, causing it to lose water ("weep"). In muscles that enter ''rigor'' in a contracted position, actin and myosin filaments overlap and cross-bond, resulting in meat that is tough on cooking – hence again the need to prevent pre-slaughter stress in the animal. Over time, the muscle proteins denature in varying degree, with the exception of the collagen and
elastin Elastin is a protein that in humans is encoded by the ''ELN'' gene. Elastin is a key component of the extracellular matrix in gnathostomes (jawed vertebrates). It is highly elastic and present in connective tissue allowing many tissues in the bod ...
of
connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
, and ''rigor mortis'' resolves. Because of these changes, the meat is tender and pliable when cooked just after death or after the resolution of ''rigor'', but tough when cooked during ''rigor.'' As the muscle pigment
myoglobin Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobi ...
denatures, its iron oxidates, which may cause a brown discoloration near the surface of the meat. Ongoing
proteolysis Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...
also contributes to conditioning. Hypoxanthine, a breakdown product of ATP, contributes to the meat's flavor and odor, as do other products of the decomposition of muscle fat and protein.


Additives

When meat is industrially processed in preparation of consumption, it may be enriched with additives to protect or modify its flavor or color, to improve its tenderness, juiciness or cohesiveness, or to aid with its preservation. Meat additives include the following: * Salt is the most frequently used additive in meat processing. It imparts flavor but also inhibits microbial growth, extends the product's shelf life and helps
emulsifying 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. Although ...
finely processed products, such as sausages. Ready-to-eat meat products normally contain about 1.5 to 2.5 percent salt. Salt water or similar substances may also be injected into poultry meat to improve the taste and increase the weight, in a process called
plumping Plumping, also referred to as “enhancing” or “injecting,” is the process by which some poultry companies inject raw chicken meat with saltwater, chicken stock, seaweed extract or some combination thereof. The practice is most commonly use ...
. *
Nitrite The nitrite polyatomic ion, ion has the chemical formula . Nitrite (mostly sodium nitrite) is widely used throughout chemical and pharmaceutical industries. The nitrite anion is a pervasive intermediate in the nitrogen cycle in nature. The name ...
is used in
curing meat Curing is any of various food preservation and flavoring processes of foods such as meat, fish and vegetables, by the addition of salt, with the aim of drawing moisture out of the food by the process of osmosis. Because curing increases the solute ...
to stabilize the meat's color and flavor, and inhibits the growth of spore-forming microorganisms such as '' C. botulinum''. The use of nitrite's precursor
nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...
is now limited to a few products such as dry sausage, prosciutto or parma ham. * Phosphates used in meat processing are normally alkaline polyphosphates such as sodium tripolyphosphate. They are used to increase the water-binding and emulsifying ability of meat proteins, but also limit lipid oxidation and flavor loss, and reduce microbial growth. * Erythorbate or its equivalent
ascorbic acid 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 ...
(vitamin C) is used to stabilize the color of cured meat. * Sweeteners such as
sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...
or
corn syrup Corn syrup is a food syrup which is made from the starch of corn (called maize in many countries) and contains varying amounts of sugars: glucose, maltose and higher oligosaccharides, depending on the grade. Corn syrup is used in foods to softe ...
impart a sweet flavor, bind water and assist surface browning during cooking in the Maillard reaction. *
Seasoning Seasoning is the process of supplementing food via herbs, spices, salts, and/or sugar, intended to enhance a particular flavour. General meaning Seasonings include herbs and spices, which are themselves frequently referred to as "seasonings". Ho ...
s impart or modify flavor. They include spices or oleoresins extracted from them,
herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...
s, vegetables and
essential oil 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 ...
s. * Flavorings such as monosodium glutamate impart or strengthen a particular flavor. * Tenderizers break down
collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
s to make the meat more palatable for consumption. They include proteolytic enzymes, acids, salt and phosphate. * Dedicated antimicrobials include lactic, citric and
acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...
, sodium diacetate, acidified
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
or calcium sulfate, cetylpyridinium chloride, activated lactoferrin, sodium or potassium lactate, or bacteriocins such as nisin. *
Antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...
s include a wide range of chemicals that limit lipid oxidation, which creates an undesirable "off flavor", in precooked meat products. * Acidifiers, most often lactic or citric acid, can impart a tangy or tart flavor note, extend shelf-life, tenderize fresh meat or help with protein denaturation and moisture release in dried meat. They substitute for the process of natural fermentation that acidifies some meat products such as hard salami or prosciutto.


Misidentification

With the rise of complex
supply chains In commerce, a supply chain is a network of facilities that procure raw materials, transform them into intermediate goods and then final products to customers through a distribution system. It refers to the network of organizations, people, activ ...
, including cold chains, in developed economies, the distance between the farmer or fisherman and customer has grown, increasing the possibility for intentional and unintentional misidentification of meat at various points in the supply chain. In 2013, reports emerged across Europe that products labelled as containing beef actually contained horse meat. In February 2013 a study was published showing that about one-third of raw fish are misidentified across the United States.Juliet Eilperin and Tim Carman for the Washington Post. February 21, 2013
One-third of seafood mislabeled, study finds


Imitation

Various forms of imitation meat have been created for people who wish not to eat meat but still want to taste its flavor and texture. Meat imitates are typically some form of processed soybean ( tofu, tempeh), but they can also be based on wheat gluten, pea protein isolate, or even fungi ( quorn).


Environmental impact

Various environmental effects are associated with meat production. Among these are greenhouse gas emissions, fossil energy use, water use, water quality changes, and effects on grazed ecosystems. The livestock sector may be the largest source of water pollution (due to animal wastes, fertilizers, pesticides), and it contributes to emergence of antibiotic resistance. It accounts for over 8% of global human water use. It is a significant driver of biodiversity loss and ecosystems, as it causes deforestation and requires large amounts of land for pasture and feed crops, ocean dead zones, land degradation, pollution,
overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...
and climate change. The occurrence, nature and significance of environmental effects varies among livestock production systems. Grazing of livestock can be beneficial for some wildlife species, but not for others. Targeted grazing of livestock is used as a food-producing alternative to herbicide use in some vegetation management.


Land use

Meat production is by far the biggest cause of land use, as it accounts for nearly 40% of the global land surface. Just in the contiguous United States, 34% of its land area () are used as pasture and rangeland, mostly feeding livestock, not counting of cropland (20%), some of which is used for producing feed for livestock. Roughly 75% of
deforested Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...
land around the globe is used for livestock pasture. Deforestation from practices like slash-and-burn releases and removes the carbon sink of grown tropical forest ecosystems which substantially mitigate climate change. The land use is a major pressure on pressure on fertile soils which is important for global food security.


Climate change

The rising global consumption of carbon-intensive meat products has "exploded the global carbon footprint of agriculture," according to some top scientists. Meat production is responsible for 14.5% and possibly up to 51% of the world's anthropogenic greenhouse gas emissions. Some nations show very different impacts to counterparts within the same group, with Brazil and Australia having emissions over 200% higher than the average of their respective income groups and driven by meat consumption. According to the '' Assessing the Environmental Impacts of Consumption and Production'' report produced by United Nations Environment Programme's (UNEP) international panel for sustainable resource management, a worldwide transition in the direction of a meat and dairy free diet is indispensable if adverse global climate change were to be prevented. A 2019 report in '' The Lancet'' recommended that global meat (and sugar) consumption be reduced by 50 percent to
mitigate climate change Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels bur ...
. Meat consumption in Western societies needs to be reduced by up to 90% according to a 2018 study published in '' Nature''. The 2019 special report by the
Intergovernmental Panel on Climate Change The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) a ...
called for significantly reducing meat consumption, particularly in wealthy countries, in order to mitigate and adapt to climate change.


Biodiversity loss

Meat consumption is considered one of the primary contributors of the sixth mass extinction. A 2017 study by the World Wildlife Fund found that 60% of global biodiversity loss is attributable to meat-based diets, in particular from the vast scale of feed crop cultivation needed to rear tens of billions of farm animals for human consumption puts an enormous strain on natural resources resulting in a wide-scale loss of lands and species. Currently, livestock make up 60% of the
biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
of all mammals on earth, followed by humans (36%) and wild mammals (4%). In November 2017, 15,364 world scientists signed a Warning to Humanity calling for, among other things, drastically diminishing our per capita consumption of meat and "dietary shifts towards mostly plant-based foods". The 2019 '' Global Assessment Report on Biodiversity and Ecosystem Services'', released by IPBES, also recommended reductions in meat consumption in order to mitigate biodiversity loss. A 2021 Chatham House report asserted that a significant shift towards plant-based diets would free up the land to allow for the restoration of ecosystems and thriving biodiversity. A July 2018 study in '' Science'' says that meat consumption is set to rise as the human population increases along with affluence, which will increase greenhouse gas emissions and further reduce biodiversity.


Reducing environmental impact

The environmental impact of meat production can be reduced by conversion of human-inedible residues of food crops. Manure from meat-producing livestock is used as fertilizer; it may be composted before application to food crops. Substitution of animal manures for synthetic fertilizers in crop production can be environmentally significant, as between 43 and 88 MJ of fossil fuel energy are used per kg of nitrogen in manufacture of synthetic nitrogenous fertilizers.


Reducing meat consumption

The IPCC and many others, including scientific reviews of the literature and data on the topic, have concluded that meat production has to be reduced substantially for any sufficient mitigation of climate change and, at least initially, largely through shifts towards plant-based diets in cases (e.g. countries) where meat consumption is high. A review names broad potential measures such as "restrictions or fiscal mechanisms". Personal Carbon Allowances that allow a certain amount of free meat consumption per person would be a form of restriction, meat taxes would be a type of fiscal mechanism. Meat can be replaced by, for example, high-protein iron-rich low-emission
legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
s and common fungi, but there are also
dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...
s (e.g. of vitamin B12 and zinc) and/or fortified foods, cultured meat (still under development), microbial foods, mycoprotein, meat substitutes, and other alternatives. Farms can be transitioned to meet new demands, workers can enter relevant job retraining programs, and land previously used for meat production can be rewilded. The biologists
Rodolfo Dirzo Rodolfo Dirzo is a professor, conservationist, and tropical ecologist. He is a Bing Professor in environmental science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment. His research interests mainly focus on plant ...
, Gerardo Ceballos, and Paul R. Ehrlich emphasize that it is the "massive planetary monopoly of industrial meat production that needs to be curbed" while respecting the cultural traditions of indigenous peoples, for whom meat is an important source of protein.


Spoilage and preservation

The spoilage of meat occurs, if untreated, in a matter of hours or days and results in the meat becoming unappetizing, poisonous or infectious. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of meat by bacteria and fungi, which are borne by the animal itself, by the people handling the meat, and by their implements. Meat can be kept edible for a much longer time – though not indefinitely – if proper hygiene is observed during production and processing, and if appropriate
food safety Food safety (or food hygiene) is used as a scientific method/discipline describing handling, preparation, and storage of food in ways that prevent food-borne illness. The occurrence of two or more cases of a similar illness resulting from t ...
,
food preservation Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit ...
and
food storage Food storage is a way of decreasing the variability of the food supply in the face of natural, inevitable variability. p.507 It allows food to be eaten for some time (typically weeks to months) after harvest rather than solely immediately. I ...
procedures are applied. Without the application of preservatives and stabilizers, the fats in meat may also begin to rapidly decompose after cooking or processing, leading to an objectionable taste known as warmed over flavor.


Methods of preparation

Fresh meat can be cooked for immediate consumption, or be processed, that is, treated for longer-term preservation and later consumption, possibly after further preparation. Fresh meat cuts or processed cuts may produce iridescence, commonly thought to be due to spoilage but actually caused by structural coloration and
diffraction Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...
of the light. A common additive to processed meats for both preservation and the prevention of discoloration is sodium nitrite. This substance is a source of health concerns because it may form carcinogenic
nitrosamine In organic chemistry, nitrosamines (or more formally ''N''-Nitrosamines) are organic compounds with the chemical structure , where R is usually an alkyl group. They feature a nitroso group () bonded to a deprotonated amine. Most nitrosamines are ...
s when heated. Meat is prepared in many ways, as steaks, in
stew A stew is a combination of solid food ingredients that have been cooked in liquid and served in the resultant gravy. A stew needs to have raw ingredients added to the gravy. Ingredients in a stew can include any combination of vegetables and ...
s, fondue, or as dried meat like beef jerky. It may be ground then formed into patties (as hamburgers or croquettes), loaves, or sausages, or used in loose form (as in "sloppy joe" or
Bolognese sauce Bolognese sauce (, ; known in Italian as ''ragù alla bolognese'', , ''ragù bolognese'', or simply ''ragù'') is a meat-based sauce in Italian cuisine, typical of the city of Bologna. It is customarily used to dress ''tagliatelle al ragù'' and ...
). Some meat is cured by
smoking Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...
, which is the process of flavoring,
cooking Cooking, cookery, or culinary arts is the art, science and craft of using heat to Outline of food preparation, prepare food for consumption. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric ...
, or preserving
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 ...
by exposing it to the smoke from burning or smoldering plant materials, most often wood. In Europe, alder is the traditional smoking wood, but oak is more often used now, and
beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...
to a lesser extent. In
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
,
hickory Hickory is a common name for trees composing the genus ''Carya'', which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexi ...
, mesquite, oak, pecan, alder, maple, and fruit-tree woods are commonly used for smoking. Meat can also be cured by pickling, preserving in salt or
brine Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
(see salted meat and other
curing A cure is a completely effective treatment for a disease. Cure, or similar, may also refer to: Places * Cure (river), a river in France * Cures, Sabinum, an ancient Italian town * Cures, Sarthe, a commune in western France People * Curate or ...
methods). Other kinds of meat are marinated and
barbecue Barbecue or barbeque (informally BBQ in the UK, US, and Canada, barbie in Australia and braai in South Africa) is a term used with significant regional and national variations to describe various cooking methods that use live fire and smoke t ...
d, or simply boiled, roasted, or fried. Meat is generally eaten cooked, but many recipes call for raw beef, veal or fish (
tartare Steak tartare or tartar steak is a dish of raw ground (minced) beef. It is usually served with onions, capers, mushrooms, pepper, Worcestershire sauce, and other seasonings, often presented separately, to be added to taste. It is often serve ...
). Steak tartare is a meat dish made from finely chopped or minced raw beef or horse meat. Meat is often spiced or seasoned, particularly with meat products such as sausages. Meat dishes are usually described by their source (animal and part of body) and method of preparation (e.g., a beef rib). Meat is a typical base for making sandwiches. Popular varieties of sandwich meat include ham, pork, salami and other sausages, and beef, such as steak, roast beef,
corned beef Corned beef, or salt beef in some of the Commonwealth of Nations, is Salt-cured meat, salt-cured brisket of beef. The term comes from the treatment of the meat with large-grained rock salt, also called "corns" of salt. Sometimes, sugar and sp ...
, pepperoni, and pastrami. Meat can also be molded or pressed (common for products that include offal, such as haggis and scrapple) and
canned Canned may refer to: * " Canned", an episode of ''Rocko's Modern Life'' * Canning of food * Dismissal (employment) * Drunkenness * produced and conserved to be released on demand, e.g. ** Canned air ** Canned hunt ** Canned laughter ** Cann ...
.


Health

There is concern and debate regarding the potential association of meat, in particular red and processed meat, with a variety of health risks. A study of 400,000 subjects conducted by the European Prospective Investigation into Cancer and Nutrition and published in 2013 showed "a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer." In 2015, the International Agency for Research on Cancer of the World Health Organization (WHO) classified processed meat as carcinogenic to humans (Group 1), based on "sufficient evidence in humans that the consumption of processed meat causes
colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel m ...
." In the same year, the Agency classified red meat as ''probably'' (Group 2A) carcinogenic to humans. The ''2015–2020
Dietary Guidelines for Americans The Dietary Guidelines for Americans (DGA) provide nutritional advice for Americans who are healthy or who are at risk for chronic disease but do not currently have chronic disease. The Guidelines are published every five years by the US Department ...
'' asked men and teenage boys to increase their consumption of vegetables or other underconsumed foods (fruits, whole grains, and dairy) while reducing intake of protein foods (meats, poultry, and eggs) that they currently overconsume. Health authorities around the world recommend limiting consumption of unprocessed red meat (such as a
beef steak A beefsteak, often called just steak, is a flat cut of beef with parallel faces, usually cut perpendicular to the muscle fibers. In common restaurant service a single serving has a raw mass ranging from . Beef steaks are usually grilled, pan ...
) and also discourage consumption of processed meat (such as bacon). In 2021, a study of data on half a million U.K. citizens shows associations between high levels of meat intake with risks of some of 25 common conditions including ischaemic heart disease and diabetes as well as a lower risk of iron deficiency anaemia. Available unde
CC BY 4.0
A cohort study with over 130,000 participants published a few days later, also found that a higher intake of processed meat was associated with "a higher risk of mortality and major CVD". However, while some of the results did control for
body mass index Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
various other factors that were not controlled for may confound the associations and research of underlying mechanisms may be required for fully robust conclusions. Studies have however concluded that plant-based diets "rich in legumes, whole grains, and nuts with reduced red and processed meats" and low in overall meat consumption (except for fish) are associated with longer life expectancy, whereby a switch from a "typical Western diet" in adults can increase life expectancy by a decade.


Contamination

Various toxic compounds can contaminate meat, including
heavy metals upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...
, mycotoxins,
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
residues,
dioxin Dioxin may refer to: * 1,2-Dioxin or 1,4-Dioxin, two unsaturated heterocyclic 6-membered rings where two carbon atoms have been replaced by oxygen atoms, giving the molecular formula C4H4O2 *Dibenzo-1,4-dioxin, the parent compound also known as ...
s, polychlorinated biphenyl (PCBs). Processed, smoked and cooked meat may contain carcinogens such as polycyclic aromatic hydrocarbons. Toxins may be introduced to meat as part of animal feed, as veterinary drug residues, or during processing and cooking. Often, these compounds can be metabolized in the body to form harmful by-products. Negative effects depend on the individual genome, diet, and history of the consumer. Any chemical's toxicity is also dependent on the dose and timing of exposure.


Cancer

There are concerns about a relationship between the consumption of meat, in particular processed and red meat, and increased cancer risk. The International Agency for Research on Cancer (IARC), a specialized agency of the World Health Organization (WHO), classified processed meat (e.g., bacon, ham, hot dogs, sausages) as, "''carcinogenic to humans'' (Group 1), based on ''sufficient evidence'' in humans that the consumption of processed meat causes colorectal cancer." IARC also classified red meat as "''probably carcinogenic to humans'' (Group 2A), based on ''limited evidence'' that the consumption of red meat causes cancer in humans and ''strong'' mechanistic evidence supporting a carcinogenic effect."


Heart disease

The correlation of consumption to increased risk of
heart disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...
is controversial. Some studies fail to find a link between red meat consumption and heart disease (although the same study found statistically significant correlation between the consumption of processed meat and coronary heart disease). A large cohort study of Seventh-Day Adventists in California found that the risk of heart disease is three times greater for 45-64-year-old men who eat meat daily, versus those who did not eat meat. This study compared adventists to the general population and not other Seventh Day Adventists who ate meat and did not specifically distinguish red and processed meat in its assessment. A Harvard University study in 2010 involving over one million people who ate meat found that only processed meat had an adverse risk in relation to coronary heart disease. The study suggests that eating 50 g (less than 2 ounces) of processed meat per day increases risk of coronary heart disease by 42%, and diabetes by 19%. Equivalent levels of fat, including saturated fats, in unprocessed meat (even when eating twice as much per day) did not show any deleterious effects, leading the researchers to suggest that "differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats." A scientific review concluded that, except for poultry, at 50 g/day unprocessed red and processed meat appear to be risk factors for ischemic heart disease, increasing the risk by about 9 and 18% respectively.


Obesity

Prospective analysis suggests that meat consumption is positively associated with weight gain in men and women. The
National Cattlemen's Beef Association National Cattlemen's Beef Association (NCBA) is an American trade association and lobbying group working for American beef producers. Advertising campaign National Cattlemen's Beef Association is a contractor to the Beef Checkoff, which is the gro ...
countered by stating that meat consumption may not be associated with fat gain. In response, the authors of the original study controlled for just abdominal fat across a sample of 91,214 people and found that even when controlling for calories and lifestyle factors, meat consumption is linked with obesity. Additional studies and reviews have confirmed the finding that greater meat consumption is positively linked with greater weight gain even when controlling for calories, and lifestyle factors.


Bacterial contamination

Bacterial contamination has been seen with meat products. A 2011 study by the Translational Genomics Research Institute showed that nearly half (47%) of the meat and poultry in U.S. grocery stores were contaminated with '' S. aureus'', with more than half (52%) of those bacteria resistant to antibiotics. A 2018 investigation by the Bureau of Investigative Journalism and '' The Guardian'' found that around 15 percent of the US population suffers from foodborne illnesses every year. The investigation also highlighted unsanitary conditions in US-based meat plants, which included meat products covered in excrement and abscesses "filled with pus".


Infectious diseases

Meat production and trade substantially increases risks for infectious diseases, including of pandemics – "directly through increased contact with wild and farmed animals zoonosis)">zoonosis.html" ;"title="zoonosis">zoonosis)or indirectly through #Environmental impact">its impact on the environment (e.g., biodiversity loss, water use, climate change)". For example, avian influenza from poultry meat production can be a threat to human health. Furthermore, the use of antibiotics in meat production contributes to antimicrobial resistance – which contributes to millions of deaths – and makes it harder to control infectious diseases.


Changes in consumer behavior

In response to changing prices as well as health concerns about saturated fat and cholesterol (see
lipid hypothesis The lipid hypothesis (also known as the cholesterol hypothesis) is a medical theory postulating a link between blood cholesterol levels and the occurrence of cardiovascular disease. A summary from 1976 described it as: "measures used to lower th ...
), consumers have altered their consumption of various meats. A USDA report points out that consumption of beef in the United States between 1970–1974 and 1990–1994 dropped by 21%, while consumption of chicken increased by 90%. During the same period of time, the price of chicken dropped by 14% relative to the price of beef. From 1995 to 1996, beef consumption increased due to higher supplies and lower prices.


Cooking

Meat can transmit certain diseases, but complete cooking and avoiding recontamination reduces this possibility. Several studies published since 1990 indicate that cooking muscle meat creates heterocyclic amines (HCAs), which are thought to increase cancer risk in humans. Researchers at the National Cancer Institute published results of a study which found that human subjects who ate beef rare or medium-rare had less than one third the risk of stomach cancer than those who ate beef medium-well or well-done. While eating muscle meat raw may be the only way to avoid HCAs fully, the National Cancer Institute states that cooking meat below creates "negligible amounts" of HCAs. Also, microwaving meat before cooking may reduce HCAs by 90%.
Nitrosamine In organic chemistry, nitrosamines (or more formally ''N''-Nitrosamines) are organic compounds with the chemical structure , where R is usually an alkyl group. They feature a nitroso group () bonded to a deprotonated amine. Most nitrosamines are ...
s, present in processed and cooked foods, have been noted as being carcinogenic, being linked to colon cancer. Also, toxic compounds called PAHs, or polycyclic aromatic hydrocarbons, present in processed, smoked and cooked foods, are known to be carcinogenic.


Sociology

Meat is part of the human diet in most cultures, where it often has symbolic meaning and important social functions. Some people choose not to eat meat (
vegetarianism Vegetarianism is the practice of abstaining from the consumption of meat (red meat, poultry, seafood, insects, and the flesh of any other animal). It may also include abstaining from eating all by-products of animal slaughter. Vegetarianism may ...
) or any food made from animals ( veganism). The reasons for not eating all or some meat may include ethical objections to killing animals for food, health concerns, environmental concerns or religious dietary laws.


Ethics

Ethical issues regarding the consumption of meat include objecting to the act of killing animals or to the agricultural practices used in meat production. Reasons for objecting to killing animals for consumption may include animal rights, environmental ethics, or an aversion to inflicting
pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
or harm on other sentient creatures. Some people, while not vegetarians, refuse to eat the flesh of certain animals (such as cows, pigs, cats, dogs, horses, or rabbits) due to cultural or religious traditions.


Philosophy

The founders of Western philosophy disagreed about the ethics of eating meat. Plato's ''
Republic A republic () is a "state in which power rests with the people or their representatives; specifically a state without a monarchy" and also a "government, or system of government, of such a state." Previously, especially in the 17th and 18th c ...
'' has Socrates describe the ideal state as vegetarian. Pythagoras believed that humans and animals were equal and therefore disapproved of meat consumption, as did Plutarch, whereas Zeno and
Epicurus Epicurus (; grc-gre, Ἐπίκουρος ; 341–270 BC) was an ancient Greek philosopher and sage who founded Epicureanism, a highly influential school of philosophy. He was born on the Greek island of Samos to Athenian parents. Influenced ...
were vegetarian but allowed meat-eating in their philosophy. Conversely, Aristotle's '' Politics'' assert that animals, as inferior beings, exist to serve humans, including as food. Augustine drew on Aristotle to argue that the universe's natural hierarchy allows humans to eat animals, and animals to eat plants.
Enlightenment Enlightenment or enlighten may refer to: Age of Enlightenment * Age of Enlightenment, period in Western intellectual history from the late 17th to late 18th century, centered in France but also encompassing (alphabetically by country or culture): ...
philosophers were likewise divided. Descartes wrote that animals are merely animated machines, and Kant considered them inferior beings for lack of discernment; means rather than ends. But Voltaire and Rousseau disagreed. The latter argued that meat-eating is a social rather than a natural act, because children are not interested in meat. Later philosophers examined the changing practices of eating meat in the
modern age The term modern period or modern era (sometimes also called modern history or modern times) is the period of history that succeeds the Middle Ages (which ended approximately 1500 AD). This terminology is a historical periodization that is applie ...
as part of a process of detachment from animals as living beings. Norbert Elias, for instance, noted that in medieval times cooked animals were brought to the table whole, but that since the Renaissance only the edible parts are served, which are no longer recognizably part of an animal. Modern eaters, according to Noëlie Vialles, demand an " ellipsis" between meat and dead animals; for instance, calves' eyes are no longer considered a delicacy as in the Middle Ages, but provoke disgust. Even in the English language, distinctions emerged between animals and their meat, such as between cattle and beef, pigs and pork. Fernand Braudel wrote that since the European diet of the 15th and 16th century was particularly heavy in meat, European colonialism helped export meat-eating across the globe, as colonized peoples took up the culinary habits of their colonizers, which they associated with wealth and power.


Religious traditions

The religion of Jainism has always opposed eating meat, and there are also
schools of Buddhism The schools of Buddhism are the various institutional and doctrinal divisions of Buddhism that have existed from ancient times up to the present. The classification and nature of various doctrinal, philosophical or cultural facets of the schools ...
and Hinduism that condemn the eating of meat. Jewish dietary rules (''
Kashrut (also or , ) is a set of dietary laws dealing with the foods that Jewish people are permitted to eat and how those foods must be prepared according to Jewish law. Food that may be consumed is deemed kosher ( in English, yi, כּשר), fro ...
'') allow certain (''
kosher (also or , ) is a set of dietary laws dealing with the foods that Jewish people are permitted to eat and how those foods must be prepared according to Jewish law. Food that may be consumed is deemed kosher ( in English, yi, כּשר), fro ...
'') meat and forbid other (''
treif (also or , ) is a set of dietary laws dealing with the foods that Jewish people are permitted to eat and how those foods must be prepared according to Jewish law. Food that may be consumed is deemed kosher ( in English, yi, כּשר), from ...
''). The rules include prohibitions on the consumption of unclean animals (such as pork,
shellfish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater envir ...
including
mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000  extant species of molluscs are recognized. The number of fossil species is esti ...
and
crustacea Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...
, and most insects), and mixtures of meat and milk. Similar rules apply in Islamic dietary laws: The Quran explicitly forbids meat from animals that die naturally, blood, the meat of swine (porcine animals, pigs), and animals dedicated to other than Allah (either undedicated or dedicated to idols) which are haram as opposed to halal. Sikhism forbids meat of slowly slaughtered animals (" kutha") and prescribes killing animals with a single strike ("
jhatka Jhatka, or Jhataka or chatka (' ), is the meat from an animal killed instantly, such as by a single strike of a sword or axe to sever the head within the Sikh religion. This type of slaughter is preferred by most Rajput in Hinduism Sikhs as well ...
"), but some Sikh groups oppose eating any meat.


Psychology

Research in applied psychology has investigated practices of meat eating in relation to morality, emotions,
cognition Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
, and personality characteristics. Psychological research suggests meat eating is correlated with
masculinity Masculinity (also called manhood or manliness) is a set of attributes, behaviors, and roles associated with men and boys. Masculinity can be theoretically understood as socially constructed, and there is also evidence that some behaviors con ...
, support for social hierarchy, and reduced openness to experience. Research into the
consumer psychology Consumer behavior is the study of individuals, groups, or organizations and all the activities associated with the purchase, use and disposal of goods and services. Consumer behaviour consists of how the consumer's emotions, attitudes, and pr ...
of meat is relevant both to meat industry marketing and to advocates of reduced meat consumption.


Gender

Unlike most other food, meat is not perceived as gender-neutral, and is particularly associated with men and
masculinity Masculinity (also called manhood or manliness) is a set of attributes, behaviors, and roles associated with men and boys. Masculinity can be theoretically understood as socially constructed, and there is also evidence that some behaviors con ...
. Sociological research, ranging from African tribal societies to contemporary
barbecue Barbecue or barbeque (informally BBQ in the UK, US, and Canada, barbie in Australia and braai in South Africa) is a term used with significant regional and national variations to describe various cooking methods that use live fire and smoke t ...
s, indicates that men are much more likely to participate in preparing meat than other food. This has been attributed to the influence of traditional male gender roles, in view of a "male familiarity with killing" (
Goody Goody, Goodies, or Goody's may refer to: Brands * Goody (brand), a brand of hair styling products owned by ACON Investments, LLC. * Goody's Powder, a pain reliever sold primarily in the southern United States * Goody's (restaurant), a fast food ...
) or
roasting Roasting is a cooking method that uses dry heat where hot air covers the food, cooking it evenly on all sides with temperatures of at least from an open flame, oven, or other heat source. Roasting can enhance the flavor through caramelization ...
being more violent as opposed to
boiling Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. Th ...
( Lévi-Strauss). By and large, at least in modern societies, men also tend to consume more meat than women, and men often prefer red meat whereas women tend to prefer chicken and fish.


See also

* Alligator meat *
Bushmeat Bushmeat is meat from wildlife species that are hunted for human consumption, most often referring to the meat of game in Africa. Bushmeat represents a primary source of animal protein and a cash-earning commodity for inhabitants of humid tropi ...
*
Carnism Carnism is a concept used in discussions of humanity's relation to other animals, defined as a prevailing ideology in which people support the use and consumption of animal products, especially meat. Carnism is presented as a dominant belief sys ...
* Culinary name *
Dog meat Dog meat is the flesh and other edible parts derived from dogs. Historically, human consumption of dog meat has been recorded in many parts of the world. During the 19th century westward movement in the United States, ''mountainmen'', native A ...
*
Food industry The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditiona ...
* Food science * Gristle * List of domesticated meat animals *
List of meat dishes This is a list of notable meat dishes. Some meat dishes are prepared using two or more types of meat, while others are only prepared using one type. Furthermore, some dishes can be prepared using various types of meats, such as the enchilada, whic ...
* List of foods * Meat Atlas * Meat on the bone *
Meat-free days Meat-free days or veggiedays are declared to discourage or prohibit the consumption of meat on certain days of the week. Mondays and Fridays are the most popular days. There are also movements encouraging people giving up meat on a weekly, monthly ...
* Mechanically separated meat * Mystery meat *
Roadkill cuisine Roadkill cuisine is preparing and eating roadkill, animals hit by vehicles and found along roads. It is a practice engaged in by a small subculture in the United States, southern Canada, the United Kingdom, and other Western countries as wel ...
* Tendon * Cat meat


References


External links

*
American Meat Science Association website

Qualitionary – Legal Definitions – Meat

IARC Monographs Q&A

IARC Monographs Q&A on the carcinogenicity of the consumption of red meat and processed meat.
{{Authority control Types of food Meat industry