Benzoic acid is a naturally occurring organic acid found in cranberries, plums, cinnamon, and other plant materials. In its commercial form, it is produced synthetically via the oxidation of toluene. Benzoic acid is one of the oldest chemical preservatives used in the food industry. It is most effective at pH levels below 4.5, where the undissociated acid form predominates and penetrates microbial cell walls to disrupt enzymatic activity.
Due to its limited water solubility, benzoic acid is often preferred for oil-phase preservation and in products where the direct acid form is more practical than sodium benzoate. It is widely used in fruit-based products, acidic beverages, and condiments. Benzoic acid is approved as a food additive in most countries and is listed as E210 in the European food additive numbering system.