sulfitecontaining

Sulfite-containing refers to substances that include the sulfite moiety, particularly the sulfite ion SO3^2− or its protonated form bisulfite HSO3−. In aqueous solution these species exist in equilibrium, and many commercial sulfite-containing compounds are salts or esters such as sodium sulfite, sodium bisulfite, and sodium metabisulfite. They are widely used as reducing agents and antioxidants; they can also release sulfur dioxide when acidified, a property exploited in some applications but with safety implications.

Sulfite-containing compounds occur naturally in small amounts in certain foods and beverages due to fermentation and processing. They are deliberately added as preservatives in a variety of foods and drinks to inhibit browning and microbial growth. Common uses include dried fruits, wines and other fruit-derived products, potato products, and some prepared foods. They also have industrial uses in photography, pulp and paper bleaching, textile processing, and water treatment.

Health and regulation: Some individuals have sulfite sensitivity, which can trigger asthma-like symptoms or other reactions after ingestion or inhalation. For this reason many jurisdictions require labeling of sulfite-containing ingredients when present above a certain threshold, typically around 10 mg/kg or 10 mg/L in foods and beverages. The presence of sulfites can also contribute to emissions as sulfur dioxide gas under certain conditions.