E210

E210 is the food additive designation for benzoic acid, a simple aromatic carboxylic acid. Its chemical formula is C7H6O2 (benzenecarboxylic acid); synonyms include benzoic acid. It has a melting point of about 122°C and a pKa near 4.2. It is sparingly soluble in water and more soluble in organic solvents. Commercial benzoic acid is produced by oxidation of toluene or via other petrochemical processes. It occurs naturally in small amounts in various fruits and essential oils.

As a preservative, E210 is valued for antimicrobial properties, particularly against yeasts and molds, at low pH. At pH below about 4.5, benzoic acid exists predominantly in its protonated form, which can diffuse into microbial cells and inhibit metabolism. It is commonly used in fruit juices, carbonated beverages, pickles, sauces, jams, and some dairy products. Related salts such as sodium benzoate (E211), potassium benzoate (E212), and calcium benzoate (E213) are also used as preservatives.

Regulatory status and safety: Benzoic acid and its salts are approved food additives in the EU, the United States, and many other jurisdictions. An acceptable daily intake for benzoic acid and its salts is typically cited as around 0–5 mg/kg body weight, depending on the authority. Safety considerations include rare hypersensitivity in some individuals and, under certain storage conditions, concerns about trace benzene formation in beverages containing benzoates and vitamin C; however, such formation is not common in properly formulated products and levels are monitored by regulators.

In summary, E210 denotes benzoic acid, a widely used preservative with natural occurrence in small amounts in foods and plants, functioning best in acidic environments and complemented by related benzoate salts.