sulphites

Salts of sulphurous acid (H₂SO₃) used as sources of sulphur dioxide (SO₂) (E-221-227).

Salts containing sulphur and usually derived from sulphur dioxide. They are used as preservatives to prevent oxidation and mould growth in many processed foods and beverages, especially wines. They were formerly used by caterers to maintain the fresh appearance of fruits and vegetables, until it was discovered that some people have an adverse reaction to sulphites. Many asthmatics, children with a history of hyperactivity, and those with liver disorders are particularly sensitive to sulphites or sulphur dioxide. Consequently, their use in raw foods has been banned in the USA. All manufacturers of processed foods must declare the sulphite content in the food label. Although sulphites are a health hazard to only a few people, it is important to be aware that they can destroy thiamin (see vitamin B₁). Foods containing appreciable quantities of sulphites will not provide this important vitamin. This may be a problem when sulphite is used to blanch chipped potatoes.