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E524Fine

Sodium hydroxide

Group: Acidity regulators

Harm level1 of 5No concern

In plain words

Sodium hydroxide (lye) is a strong alkali used in food processing, for example to treat pretzels, olives or cocoa. It is neutralised in the finished food, so it does not reach you as a caustic substance.

Where you find it: pretzels, olives, cocoa

Our recommendation

No need to avoid it.

Possible risks and effects

  • No relevant risk known at normal intake.
  • Only concentrated lye is hazardous during handling, not the finished food.

For experts

A strong inorganic base used as an acidity regulator and processing aid (peeling, debittering olives, cocoa alkalisation, lye pretzels). During processing it reacts with acids and CO2 to ordinary sodium salts; authorised in the EU at quantum satis.

Check another E-number

More from this group

E338Phosphoric acidE339Sodium phosphatesE340Potassium phosphatesE341Calcium phosphatesE450DiphosphatesE451TriphosphatesE452PolyphosphatesE325Sodium lactate

This information is educational and based on EFSA assessments and available studies; it does not replace medical advice. With allergies, intolerances or illness, follow your doctor’s advice.