E252: Potassium nitrate

What is E252?

Potassium nitrate, also known as saltpetre and labelled E252, is a crystalline salt of potassium and nitrate. It has been used in curing meat for centuries.

Origin and production

Today it is mostly produced industrially by reacting potassium chloride with nitric acid or sodium nitrate; it also occurs as a natural mineral.

Why is it used?

In cured meats, bacteria gradually convert potassium nitrate into nitrite, which fixes the characteristic pink colour, contributes to flavour and helps protect against harmful bacteria such as Clostridium botulinum. It is typical of slow-cured products such as dry sausages, salami and dry-cured hams.

Vegan, vegetarian and halal

Potassium nitrate is mineral-derived and suitable for vegans and vegetarians in itself, although it is used mainly in meat products. It is not a halal or kosher concern on its own.

Safety and regulation

Potassium nitrate is authorised in the EU with strict maximum levels, because nitrites formed from it can lead to nitrosamines. EFSA's re-evaluation found that nitrate from all dietary sources, mostly vegetables, can lead to exceeding the acceptable daily intake for some population groups.

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