E211 Preservative

E211 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 frozen yogurt toppings. It is also used as a preservative in medicines and cosmetics. Under these conditions, it is converted into (E210), which is bacteriostatic and fungistatic. E211 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. E211 is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials. E211 has been replaced by potassium sorbate in the majority of soft drinks in the United Kingdom.

E211 was one of the chemicals used in 19th century industrialized food production that was investigated by Dr. Harvey W. Wiley with his famous 'Poison Squad' as part of the US Department of Agriculture. This led up to the 1906 Pure Food and Drug Act, a landmark event in the early history of food regulation in the United States.