E224

E224 is the European food additive designation for potassium metabisulfite, a sulfur-containing preservative and antioxidant used in a range of foods and drinks. In water, it hydrolyzes to sulfite ions and sulfur dioxide, which contribute to antimicrobial effects and help prevent browning and oxidation. It is commonly used in dried fruits, wines and fruit juices, canned vegetables, pickles, shrimp and other seafood, and some processed condiments and bakery products.

Applications and function: as a preservative, E224 helps extend shelf life by inhibiting microbial growth and reducing enzymatic browning. It also acts as an antioxidant, protecting color and flavor in susceptible products. Its use is governed by product-specific regulations that set maximum permitted levels.

Safety and regulation: sulfites, including potassium metabisulfite, can provoke adverse reactions in sulfite-sensitive individuals, ranging from mild symptoms to asthma-like reactions. Labeling rules require that sulfites be declared on the ingredients list when present above certain thresholds (commonly around 10 mg/kg or 10 mg/L, depending on jurisdiction). Maximum allowed levels vary by product category and regional regulations, and some organic products restrict or prohibit sulfite additives.

Chemistry and handling: E224 is typically used in solid form and added to foods where its preservative action is desired. It releases sulfite and sulfur dioxide upon dissolution, which drives its antimicrobial and anti-browning effects. Proper storage and adherence to regulatory limits are important to ensure safety and compliance.