E521 · Firming agents

Aluminium sodium sulphate

High risk

Avoid when possible to minimize dietary aluminum exposure.

Category: Firming agents
Vegan: Yes
Vegetarian: Yes

What it is

Aluminium sodium sulphate is a light-metal salt used as a firming agent and raising-agent component.

How it is used in food

Firms texture and, in baking powders, controls when the rise happens.

Commonly found in

Pickled vegetables (historical)
Candied fruits

Health and safety

The concern is the aluminium, which accumulates in bone and tissue and clears slowly. EFSA's tolerable weekly intake is 1 mg per kg of body weight, and some European diets already reach it without any help from additives — so the sensible move is to drop the avoidable sources.

Health authorities recommend limiting overall dietary aluminum intake to avoid neurological risks.

Aluminium Accumulation

General population · evidence: suspected

Aluminium from food additives can accumulate in the body over time, which has been controversially linked to neurological conditions.

Authorised in the EU, with permitted uses cut back in 2012 to reduce total dietary aluminium. EFSA's tolerable weekly intake is 1 mg/kg body weight.

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: E521

Also printed asAluminium sodium sulfate · aluminum sodium sulfate · aluminum sodium sulphate

Worth knowing

It is one of the alums, the family of double sulphates used for centuries in dyeing and water treatment before anyone put them in food.

Conclusion

Avoid when possible to minimize dietary aluminum exposure.

References

EFSA Safety Assessment

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Entry last reviewed 2026-07-28.

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