Sodium benzoate is the sodium salt of

benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, w ...

, widely used as a

food preservative 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 inhi ...

(with an

E number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C₆H₅COONa.

Production

Sodium benzoate is commonly produced by the neutralization of

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkal ...

(NaOH) with

(C₆H₅COOH), which is itself produced commercially by

partial oxidation Partial oxidation (POX) is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell. A d ...

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) ...

with

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as we ...

Natural occurrence

Many foods are natural sources of benzoic acid, its salts, and its esters.

Fruits In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particul ...

and

vegetables Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the edible flower, flowers, ...

can be rich sources, particularly berries such as

cranberry Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus ''Oxycoccus'' of the genus '' Vaccinium''. In Britain, cranberry may refer to the native species '' Vaccinium oxycoccos'', while in North America, cranber ...

and

bilberry Bilberries (), or sometimes European blueberries, are a primarily Eurasian species of low-growing shrubs in the genus '' Vaccinium'' (family Ericaceae), bearing edible, dark blue berries. The species most often referred to is '' Vaccinium myrt ...

. Other sources include

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 a ...

, such as prawns, and

dairy products 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 ...

Uses

As a preservative

Sodium benzoate can act as a food preservative. It is most widely used in acidic foods such as

salad dressings A salad dressing is a sauce for salads. Used on virtually all '' leafy salads'', dressings may also be used in making salads of beans (such as three bean salad), noodle or pasta salads and antipasti, and forms of potato salad. Salad dressings ...

(for example

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 componen ...

vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to ...

carbonated drinks A soft drink (see § Terminology for other names) is a drink that usually contains water (often carbonated), a sweetener, and a natural and/or artificial flavoring. The sweetener may be a sugar, high-fructose corn syrup, fruit juice, a s ...

( carbonic acid), jams and

fruit juices Juice is a drink made from the extraction or pressing of the natural liquid contained in fruit and vegetables. It can also refer to liquids that are flavored with concentrate or other biological food sources, such as meat or seafood, such a ...

(

citric acid Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in t ...

), pickles (

condiment A condiment is a preparation that is added to food, typically after cooking, to impart a specific flavor, to enhance the flavor, or to complement the dish. A table condiment or table sauce is more specifically a condiment that is served separat ...

s, and frozen yogurt toppings. It is also used as a preservative in medicines and cosmetics. Under these conditions it is converted into

(E210), which is bacteriostatic and fungistatic. Benzoic acid is generally not used directly due to its poor water solubility. Concentration as a food preservative is limited by the FDA in the U.S. to 0.1% by weight. Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials. Sodium benzoate has been replaced by

potassium sorbate Potassium sorbate is the potassium salt of sorbic acid, chemical formula CH3CH=CH−CH=CH−CO2K. It is a white salt that is very soluble in water (58.2% at 20 °C). It is primarily used as a food preservative (E number 202). Potassium sor ...

in the majority of soft drinks in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

. Sodium benzoate was one of the chemicals used in 19th century industrialised food production that was investigated by Dr.

Harvey W. Wiley Harvey Washington Wiley (October 18, 1844 – June 30, 1930) was an American chemist who fought for the passage of the landmark Pure Food and Drug Act of 1906 and subsequently worked at the Good Housekeeping Institute laboratories. He wa ...

with his famous 'Poison Squad' as part of the

US Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of comm ...

. This led up to the 1906

Pure Food and Drug Act The Pure Food and Drug Act of 1906, also known as Dr. Wiley's Law, was the first of a series of significant consumer protection laws which was enacted by Congress in the 20th century and led to the creation of the Food and Drug Administratio ...

, a landmark event in the early history of food regulation in the United States.

In pharmaceuticals

Sodium benzoate is used as a treatment for urea cycle disorders due to its ability to bind amino acids. This leads to excretion of these amino acids and a decrease in ammonia levels. Recent research shows that sodium benzoate may be beneficial as an add-on therapy (1 gram/day) in

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wi ...

.Add-on Treatment of Benzoate for Schizophrenia A Randomized, Double-blind, Placebo-Controlled Trial of d-Amino Acid Oxidase Inhibitor
December 2013 Total Positive and Negative Syndrome Scale scores dropped by 21% compared to placebo. Sodium benzoate, along with

phenylbutyrate Sodium phenylbutyrate, sold under the brand name Buphenyl among others, is a salt of an aromatic fatty acid, 4-phenylbutyrate (4-PBA) or 4-phenylbutyric acid. The compound is used to treat urea cycle disorders, because its metabolites offer an ...

, is used to treat hyperammonemia. Sodium benzoate, along with

caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally as a cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine t ...

, is used to treat

postdural puncture headache Post-dural-puncture headache (PDPH) is a complication of puncture of the dura mater (one of the membranes around the brain and spinal cord). The headache is severe and described as "searing and spreading like hot metal", involving the back and fro ...

, respiratory depression associated with overdosage of narcotics, and with ergotamine to treat

vascular headache A vascular headache is an outdated term to describe certain types of headache which were thought to be related to blood vessel swelling and hyperemia as cause of pain. There is no doubt that ''some'' headaches are caused by vascular effects. How ...

Other uses

Sodium benzoate is also used in

fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...

as a fuel in whistle mix, a powder that emits a whistling noise when compressed into a tube and ignited.

Mechanism of food preservation

The mechanism starts with the absorption of benzoic acid into the cell. If the intracellular pH falls to 5 or lower, the anaerobic fermentation of

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, usi ...

through phosphofructokinase decreases sharply, which inhibits the growth and survival of microorganisms that cause food spoilage.

Health and safety

In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, sodium benzoate is designated as generally recognized as safe (GRAS) by the

Food and Drug Administration 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 ...

. The International Programme on Chemical Safety found no adverse effects in humans at doses of 647–825 mg/kg of body weight per day. Cats have a significantly lower tolerance against benzoic acid and its

salts In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively ...

than rats and mice. The human body rapidly clears sodium benzoate by combining it with

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid ( carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinog ...

to form

hippuric acid Hippuric acid ( Gr. ''hippos'', horse, ''ouron'', urine) is a carboxylic acid and organic compound. It is found in urine and is formed from the combination of benzoic acid and glycine. Levels of hippuric acid rise with the consumption of phenolic ...

which is then excreted. The metabolic pathway for this begins with the conversion of benzoate by butyrate-CoA ligase into an intermediate product,

benzoyl-CoA Benzoyl-CoA is a molecule implied in the activity of the different enzymes 4-hydroxybenzoyl-CoA reductase, benzoyl-CoA reductase, benzoyl-CoA 3-monooxygenase, benzoate-CoA ligase, 2alpha-hydroxytaxane 2-O-benzoyltransferase In enzymology, a 2al ...

, which is then metabolized by glycine ''N''-acyltransferase into hippuric acid.

Association with benzene in soft drinks & pepper sauces

In combination with

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) a ...

(vitamin C, E300), sodium benzoate and potassium benzoate may form

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen ato ...

. In 2006, the Food and Drug Administration tested 100 beverages available in the United States that contained both ascorbic acid and benzoate. Four had benzene levels that were above the 5 ppb Maximum Contaminant Level set by the

Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...

for drinking water. Most of the beverages that tested above the limit have been reformulated and subsequently tested below the safety limit. Heat, light and shelf life can increase the rate at which benzene is formed. Hot peppers naturally contain vitamin C ("nearly as much as in one orange"https://www.ahchealthenews.com/2016/11/04/hot-sauce-good-health/) so the observation about beverages applies to pepper sauces containing sodium benzoate, like Texas Pete.

Hyperactivity

Research published in 2007 for the UK's

Food Standards Agency , type = Non-ministerial government department , nativename = , nativename_a = , nativename_r = , logo = Food Standards Agency.svg , logo_width = , logo_caption = , seal = , seal_width = , seal_caption = , picture = , picture_width = , ...

(FSA) suggests that certain artificial colors, when paired with sodium benzoate, may be linked to

hyperactive Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inapp ...

behavior. The results were inconsistent regarding sodium benzoate, so the FSA recommended further study.Food Standards Agency issues revised advice on certain artificial colours
6 September 2007Food Colorings and Hyperactivity
"Myomancy" 7 September 2007Agency revises advice on certain artificial colours
Food Standards Agency, 11 September 2007 The Food Standards Agency concluded that the observed increases in hyperactive behavior, if real, were more likely to be linked to the artificial colors than to sodium benzoate. The report's author, Jim Stevenson from

Southampton University , mottoeng = The Heights Yield to Endeavour , type = Public research university , established = 1862 – Hartley Institution1902 – Hartley University College1913 – Southampton University Coll ...

, said: "The results suggest that consumption of certain mixtures of artificial food colours and sodium benzoate preservative are associated with increases in hyperactive behaviour in children. . . . Many other influences are at work but this at least is one a child can avoid."

Compendial status

British Pharmacopoeia The ''British Pharmacopoeia'' (''BP'') is the national pharmacopoeia of the United Kingdom. It is an annually published collection of quality standards for medicinal substances in the UK, which is used by individuals and organisations invo ...

European Pharmacopoeia The ''European Pharmacopoeia'' (''Pharmacopoeia Europaea'', ''Ph. Eur.'') is a major regional pharmacopoeia which provides common quality standards throughout the pharmaceutical industry in Europe to control the quality of medicines, and the s ...

* Food Chemicals Codex * Japanese Pharmacopoeia *

United States Pharmacopeia The ''United States Pharmacopeia'' (''USP'') is a pharmacopeia (compendium of drug information) for the United States published annually by the United States Pharmacopeial Convention (usually also called the USP), a nonprofit organization tha ...

References

External links

International Programme on Chemical Safety - Benzoic Acid and Sodium Benzoate report
*

The Ketchup Conundrum
{{DEFAULTSORT:Sodium Benzoate Antiseptics Benzoates Preservatives Organic sodium salts E-number additives