Sodium benzoate is a substance which has the chemical formula C6H5COONa. It is a widely used food preservative, with an E number of E211. It is the sodium salt of benzoic acid and exists in this form when dissolved in water. It can be produced by reacting sodium hydroxide with benzoic acid.
Sodium benzoate is a preservative, with the E number E211. It is most widely used in acidic foods such as salad dressings (i.e. acetic acid in vinegar), carbonated drinks (carbonic acid), jams and fruit juices (citric acid), pickles (acetic acid), condiments, and frogurt toppings. It is also used as a preservative in medicines and cosmetics. Under these conditions it is converted into benzoic acid (E210), which is bacteriostatic and fungistatic. Benzoic acid is generally not used directly due to its poor water solubility. Concentration as a food preservative is limited by the FDA in the U.S. to 0.1% by weight. Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials. Sodium benzoate has been replaced by potassium sorbate in the majority of soft drinks in the United Kingdom.