Potassium hydrogen sulphite

Potassium hydrogen sulphite is a potassium-based sulphiting agent that releases sulphur dioxide in acidic food environments, serving as a preservative and antioxidant. It is used in wine making, dried fruit processing, and other applications where SO₂-mediated preservation is needed. Its function is indistinguishable from other sulphite additives: SO₂ released from the compound inhibits oxidative enzymes, prevents non-enzymatic browning, and suppresses microbial activity, collectively protecting colour, flavour, and shelf life.

JECFA assessed potassium hydrogen sulphite as part of the sulphite group in 1967 and applied the collective group ADI of 0.7 mg/kg body weight per day expressed as SO₂. This group approach reflects that all sulphite compounds ultimately contribute to the same pool of SO₂ in food, making their effects and risks equivalent regardless of the specific salt form. The ADI is derived from studies examining the effects of SO₂ on organ function and microbial ecology at relevant exposure levels.

Potassium hydrogen sulphite is approved in the EU as E228 for use in specific food categories. Mandatory allergen declaration requirements apply when sulphite content exceeds 10 mg/kg SO₂, ensuring transparency for sulphite-sensitive consumers. The allergy risk profile of E228 is identical to that of all other sulphite preservatives: sensitive individuals, particularly those with asthma, may experience respiratory symptoms following consumption of sulphite-containing foods. Consumers with known sulphite sensitivity should monitor their intake across the entire E220–E228 range rather than focusing on any single sulphite additive, as the physiological effect is cumulative and depends on total SO₂ exposure.