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Potassium benzoate

Potassium benzoate
IUPAC name Potassium benzoate
Other names Benzoic acid, potassium salt
CAS number 582-25-2
PubChem 11399
EINECS number 209-481-3
SMILES C1=CC=C(C=C1)C(=O)[O-].[K+]
Molecular formula C7H5KO2
Molar mass 160.2117
Appearance White solid
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Potassium benzoate, the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low-pH products, below 4.5, where it exists as benzoic acid.

Acidic foods and beverages such as fruit juice (citric acid), sparkling drinks (carbonic acid), soft drinks (phosphoric acid), and pickles (vinegar) are preserved with potassium benzoate.

It is approved for use in most countries including Canada, the U.S., and the EU, where it is designated by the E number E212. In the EU, it is not recommended for consumption by children.[1]

Mechanism of food preservation

The mechanism of food preservation begins with the absorption of benzoic acid into the cell. If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%.[2]

Safety and health

Main article: benzene in soft drinks

In combination with ascorbic acid (vitamin C), sodium and potassium benzoate may form benzene, a known carcinogen. Heat, light and shelf life can affect the rate at which benzene is formed. The Food and Drug Administration (FDA) is currently (as of March 2006) performing tests, but the Environmental Working Group is calling for the FDA to publicly release all tests and use their authority to force companies to reformulate to avoid the potential benzene forming combination.[3]

Potassium Benzoate (or E212) was recently described by the Food Commission, who campaign for 'safer, healthier food in the UK', as "mildly irritant to the skin, eyes and mucous membranes". [4]

Cats have a significantly lower tolerance to benzoic acid and its salts than rats and mice.[5]


  1. ^ Cosmetic Ingredient Review Expert Panel Bindu Nair (2001). "Final Report on the Safety Assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate". Int J Tox (20 (Suppl. 3)): 23-50.
  2. ^ Krebs HA, Wiggins D, Stubbs M (1983). "Studies on the mechanism of the antifungal action of benzoate". Biochem J (214): 657-663.
  3. ^ Press Release from the Environmental Working Group
  4. ^ Published in The Food Magazine issue 77from the Food Commission UK
  5. ^ Bedford PG, Clarke EG (1972). "Experimental benzoic acid poisoning in the cat". Vet Rec (90): 53-58. PMID 4672555
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Potassium_benzoate". A list of authors is available in Wikipedia.
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