E526

Calcium hydroxide

No known risk

Pickling lime, processing aid.

Vegan: Yes
Vegetarian: Yes

What it is

A strong alkaline base used to rapidly raise pH, peel fruits, or alter the surface texture of baked goods.

How it is used in food

Critical for the traditional Mesoamerican process of nixtamalization, which makes corn more nutritious and easier to grind into masa.

Commonly found in

Pretzels
Bagels
Canned olives
Cocoa processing

Health and safety

None in the finished food. It is neutralised in use, leaving calcium.

Permitted as a processing aid; a technique documented in Mesoamerica for over three thousand years.

Regulatory status

Region	Status	Notes
Australia & New Zealand FSANZ	Permitted	Permitted under the FSANZ Food Standards Code.
European Union EFSA / European Commission	Permitted	Authorised for food use under EU regulations (Annex II).
United States FDA (Food and Drug Administration)	Permitted	Authorised for food use by the FDA (often GRAS for standard additives).

Identification on labels

E-number: E526

How it is made

Synthesized industrially from basic mineral and chemical feedstocks.

Nixtamalization — Dried corn kernels are soaked and cooked in an alkaline solution (calcium hydroxide), which loosens the hulls and releases bound niacin (Vitamin B3).

Worth knowing

Also known as 'slaked lime', it was traditionally made by boiling limestone or burning seashells.

Conclusion

There is no reason to avoid calcium hydroxide in food products. Used for thousands of years in the nixtamalization of corn for masa, this alkaline base is fully neutralised during processing and leaves only dietary calcium behind. EFSA approves its use as a completely safe processing aid.

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Entry last reviewed 2026-07-28.

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