It works best in low-pH products, below 4.5, where it exists as benzoic acid.

It is approved for use in most countries including Canada, the United States and the European Union, where it is designated by the E number E212.

If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%.

Potassium benzoate has low acute toxicity upon oral and dermal exposure.

[6] The Food Commission, which campaigns for safer, healthier food in the UK, describes potassium benzoate as "mildly irritant to the skin, eyes and mucous membranes".