E523: Aluminium Ammonium Sulphate
Main role: firming specified foods
Also listed as: ammonium alum, aluminum ammonium sulfate
What is E523 (Aluminium Ammonium Sulphate)?
E523 is ammonium alum, a double sulphate salt containing aluminium and ammonium. It has its own specification within the alum ingredient family and is subject to limited food-use conditions.
What does it do in food?
Its main role is firming specified foods. Mineral ingredients can adjust acidity, firm a food, or keep powders flowing. A technical mineral ingredient does not establish a nutritional dose; use the nutrition declaration to assess amounts per serving.
Food and formulation examples
- Specified fruit preparations
- Narrowly authorized firming applications
These examples describe formulation roles, not a list of unrestricted legal uses. Availability and permitted applications differ by country and food category.
Label names and ingredient questions
Look for E523, E 523, or the ingredient name. Related names and label terms include ammonium alum, aluminum ammonium sulfate. A family code can cover more than one specified form; check the full declaration when the distinction matters.
Ammonium alum differs from ammonium sulphate E517. The additional aluminium component and the exact food-use authorization matter when comparing the ingredients.
Is E523 safe?
EFSA’s 2018 review assessed aluminium sulphates and acidic sodium aluminium phosphate specifically. This is a different assessment from the 2019 review of other phosphate additives. EFSA aluminium-containing additives review (2018).
A label identifies the ingredient but usually not its concentration. Calculating daily intake requires the amount in the food and the quantities eaten.
Authorization and conditions of use
The Great Britain food additive register lists E523 as Aluminium ammonium sulphate. This is an entry subject to its stated conditions, not unrestricted permission for every food. The record links to the applicable authorization terms. For an EU product, use the European Commission food additive database to check the relevant food category and limits. Other countries may use different names or rules.