Benzoic Acid vs Sorbic Acid: which is worse?

What is Benzoic Acid?

Benzoic acid is a naturally occurring aromatic carboxylic acid found in cranberries, prunes, cinnamon, and many berries. It is used as a preservative against bacteria, yeast, and fungi at pH below 4.5. In the body, benzoic acid is conjugated with glycine to form hippuric acid, which is excreted in urine.

What is Sorbic Acid?

Sorbic acid is an unsaturated fatty acid naturally occurring in the berries of the rowan tree (Sorbus aucuparia). Commercially, it is produced synthetically and used as a broad-spectrum antimicrobial preservative, effective primarily against molds and yeasts, and to a lesser extent bacteria, at acidic to neutral pH.

Documented risks

Benzoic Acid: When benzoic acid (or sodium benzoate) is combined with ascorbic acid (vitamin C) in beverages, it can form benzene, a known carcinogen classified as Group 1 by IARC. This reaction is promoted by heat and light. The FDA and EFSA monitor benzene levels in beverages and have set informal guidance limits. A 1999 Lancet publication and the subsequent 2007 'Southampton study' did not directly involve benzoic acid, but sodium benzoate was included in the tested mixture. Some individuals with aspirin sensitivity may react to benzoic acid. The ADI is 5 mg/kg body weight/day.

Sorbic Acid: One of the safest preservatives in use. Sorbic acid is metabolized normally as a short-chain fatty acid and poses no identified carcinogenic, mutagenic, or reproductive risks. The ADI (Acceptable Daily Intake) is 25 mg/kg body weight/day, and typical dietary exposure is well below this threshold. Rare skin sensitization has been reported in cosmetic contexts but is not relevant to food consumption. EFSA and FDA both classify it as safe.