Potassium Metabisulphite

Potassium metabisulfite is a white or slightly yellowish crystalline powder. It is a salt of sulfurous acid, produced by reacting potassium carbonate or potassium hydroxide with sulfur dioxide. It is often used as a preservative and antioxidant.

Manufacturers add potassium metabisulfite to foods as a preservative to prevent spoilage and maintain color. It is commonly found in dried fruits, wines, and some processed vegetables. It works by inhibiting the growth of bacteria and molds.

In the U.S., potassium metabisulfite is generally recognized as safe (GRAS) by the FDA when used according to good manufacturing practices. It is a sulfite, and some individuals, particularly those with asthma, may be sensitive to sulfites, experiencing allergic-type reactions. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has evaluated sulfites, including potassium metabisulfite, and established acceptable daily intakes. Evidence regarding the effects of sulfites at typical consumption levels is mixed, with most concerns focused on sulfite-sensitive individuals.