Sodium benzoate has the chemical formula NaC7H5O2; it is a widely used food preservative, with
E number E211. It is the sodium salt of benzoic acid and exists in this form when dissolved
in water. It can be produced by reacting sodium hydroxide with benzoic acid. Benzoic acid
occurs naturally at low levels in cranberries, prunes, greengage plums, cinnamon, ripe cloves,
and apples.
Uses Preservative
Sodium benzoate is a preservative. As a food additive, sodium benzoate has the E number
E211. It is bacteriostatic and fungistatic under acidic conditions. It is most widely
used in acidic foods such as salad dressings, carbonated drinks, jams and fruit juices,
pickles, and condiments. It is also used as a preservative in medicines and cosmetics.
Concentration as a 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%, according to
AFCO's official publication. Pharmaceutical applications
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
in schizophrenia. Total Positive and Negative Syndrome Scale scores dropped by 21% compared
to placebo. Sodium benzoate is used to treat hyperammonemia.
Sodium benzoate has been shown to halt the progression of Parkinson's in mice.
Other uses Sodium benzoate is also used in fireworks
as a fuel in whistle mix, a powder that emits a whistling noise when compressed into a tube
and ignited. The fuel is one of the fastest-burning rocket fuels and provides a lot of thrust
and smoke. It is sensitive to impact and can explode when sharply compressed.
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 through phosphofructokinase decreases sharply which inhibits the growth and survival
of micro-organisms that cause food spoilage. Production
Sodium benzoate is produced by the neutralization of benzoic acid with sodium hydroxide. Sodium
benzoate can also be prepared by adding benzoic acid to a hot concentrated solution of sodium
carbonate until effervescence ceases. The solution is then evaporated, cooled and allowed
to crystallize or evaporate to dryness, and then granulated.
Health and safety In the United States, sodium benzoate is designated
as generally recognized as safe by the Food and Drug Administration. 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 than rats and mice.
Association with benzene in soft drinks
In combination with ascorbic acid, sodium benzoate and potassium benzoate form benzene,
a known carcinogen. When tested by the FDA, most beverages that contained both ascorbic
acid and benzoate had benzene levels that were below those considered dangerous for
consumption by the World Health Organization. Most of the beverages that tested higher have
been reformulated and subsequently tested below the safety limit. Heat, light and shelf
life can increase the rate at which benzene is formed.
Hyperactivity Research published in 2007 for the UK's Food
Standards Agency suggests that certain artificial colors, when paired with sodium benzoate may
be linked to hyperactive behavior. The results were inconsistent regarding sodium benzoate,
so the FSA recommended further study. 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,
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." In response to consumer insistence on a more
natural product, the Coca Cola Company is in the process of phasing sodium benzoate
out of Diet Coke. The company has stated it plans to remove sodium benzoate from its other
products — including Sprite, Fanta, and Oasis — as soon as a satisfactory alternative
is discovered. Compendial status
British Pharmacopoeia European Pharmacopoeia
Food Chemicals Codex Japanese Pharmacopoeia
United States Pharmacopeia 29 See also
Acceptable daily intake Food-induced purpura
Potassium benzoate References
External links International Programme on Chemical Safety
- Benzoic Acid and Sodium Benzoate report Kubota K, Ishizaki T. "Dose-dependent pharmacokinetics
of benzoic acid following oral administration of sodium benzoate to humans". Eur. J. Clin.
Pharmacol. 41: 363–8. doi:10.1007/BF00314969. PMID 1804654. "Although the maximum rate
of biotransformation of benzoic acid to hippuric acid varied between 17.2 and 28.8 mg.kg-1.h-1
among the six individuals, the mean value was fairly close to that provided by daily
maximum dose recommended in the treatment of hyperammonaemia in patients with inborn
errors of ureagenesis" Andersen A. "Final report on the safety assessment
of benzaldehyde". Int. J. Toxicol. 25: 11–27. doi:10.1080/10915810600716612. PMID 16835129.
Sodium Benzoate A Cause of Hyper Kids Safety data for sodium benzoate
The Ketchup Conundrum