What is E224?

Potassium metabisulfite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent odour. It is mainly used as an antioxidant or chemical sterilant. E224 sits in the E200–E299 series, which in the EU classification mainly covers preservatives.

What is E224 used for?

E224 belongs to the preservatives group. Preservatives stop food from spoiling by slowing bacteria, mould and yeast. Most are safe, though some people limit certain ones.

Is E224 safe?

E224 is rated “moderate”. It is approved for use in food, but some people prefer to limit it. “Moderate” means it is approved, but is debated or something some people prefer to limit.

How E224 appears on labels

On food packaging you'll find E224 either as the number “E224” or by the name “Potassium metabisulphite” in the ingredient list, often after its function. Ingredients are listed in descending order by weight, so an additive near the end is present only in small amounts.

Is E224 vegan?

Yes, E224 is suitable for vegans.