E224: Potassium metabisulphite
What is E224?
Potassium metabisulphite (E224) is a white crystalline salt that releases sulphur dioxide when dissolved in acidic conditions. It belongs to the sulphite family of additives, numbered E220 to E228.
Origin and production
It is produced synthetically by reacting sulphur dioxide with potassium hydroxide or potassium carbonate.
Why is it used?
The sulphur dioxide it releases acts as both a preservative, inhibiting yeasts, moulds and bacteria, and an antioxidant that prevents browning. It is a classic additive in wine and is also used in Dijon and other mustards, bottled lemon juice, sauces and some dried fruits.
Vegan, vegetarian and halal
Potassium metabisulphite is a synthetic mineral compound and suitable for vegans and vegetarians. It raises no specific halal or kosher issue on its own, although the foods it is used in may.
Safety and regulation
Sulphites are authorised in the EU but must be declared as an allergen when present above 10 mg per kg or litre, because they can trigger reactions in some sensitive people, notably some with asthma. EFSA identified a risk of exceeding the acceptable daily intake for some population groups.
Written by the Foodlas editorial team with AI assistance and checked against EU Regulation (EC) No 1333/2008 and EFSA scientific opinions. Last reviewed: October 14, 2026.
Sources: Regulation (EC) No 1333/2008 · EFSA — Food additives · Wikidata
Common in
Products containing E224
