Sulphites (Canadian and English spelling) or sulfites (U.S. spelling) are a naturally occurring substance in some foods and the human body, but are added to prepared foods, beverages and medications as preservatives, and to enhance colour. They are added to packaging such as cellophane in some instances.
They are also called:
E 220, E 221, E 222, E 223, E 224, E 225, E 226, E 227, E 228 (European names)
Potassium bisulphite/metabisulphite
Sodium bisulphite/dithionite/metabisulphite/sulphite
Sulfur dioxide
Sulphur dioxide
Sulphiting agents
Sulphurous acid