International Numbering System (INS) for Food Additives: 220
Food additives Europe numbers: E220
Functional Category
Antimicrobial preservative; antioxidant.
Applications in Pharmaceutical Formulation
Sulfur dioxide is used as an antioxidant for pharmaceutical injections. It is also used as a preservative and antioxidant in the food and cosmetics industries.
Description
Sulfur dioxide occurs as a colorless gas at room temperature and pressure, with a strong, suffocating, pungent odor. It is noncombustible and is a strong reducing agent.
Stability and Storage Conditions
Sulfur dioxide is noncorrosive and stable when dry. It is usually stored under pressure in cylinders, and should be kept in a cool, dry, well-ventilated area, away from flammable materials.
Incompatibilities
Sulfur dioxide reacts vigorously with strong alkalis and oxidizing agents. The moist gas corrodes most metals. Sulfur dioxide is incompatible with chlorates, fluorine, interhalogens, powdered metals, metal oxides, metal acetylides, sodium hydroxide, and diethyl zinc. It is also incompatible with thiamine and gelatin. See further details under Sodium metabisulfite
Safety
Sulfur dioxide is used in food and pharmaceutical products. However, in large amounts, sulfur dioxide gas is highly irritant to the eyes, skin, and mucous membranes. Inhalation can lead to severe irritation of the respiratory tract. Direct contact with the liquid form may cause frostbite. Sulfur dioxide and sulfites may also cause allergic reactions and asthma.(1–3)