Naturally Occurring Sulfur Dioxide

Sulfur dioxide (SO2) is a gas that occurs naturally in small amounts in some foods and is also produced during fermentation. It can be added to foods as a preservative or antioxidant. It is produced industrially by burning sulfur or by heating metal sulfides.

Sulfur dioxide is often added to dried fruits, wines, and processed foods to prevent spoilage and maintain color. It acts as an antioxidant, preventing browning and preserving flavor. It is also used as a preservative in some sauces and dressings.

Sulfur dioxide is generally recognized as safe (GRAS) by the FDA when used as a food additive. It can cause allergic-type reactions in sensitive individuals, particularly those with asthma. JECFA and EFSA have evaluated sulfur dioxide and set acceptable daily intakes. While generally considered safe at typical levels, some research suggests potential adverse effects in sensitive populations.