Aluminium ammonium sulphate is the acidity regulator the food industry lists as E523. In our table it is moderate risk: it takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100).
- The key finding, from EFSA: Aluminium sulphates E 520 to 523 of no safety concern at current EU authorised uses (niche exposure); no genotoxicity or carcinogenicity concern; P95 aluminium exposure up to 0.88 mg/kg bw/day in toddlers and children flagged as highly uncertain (EFSA Journal 2018;16(7):5372, doi:10.2903/j.efsa.2018.5372, Re-evaluation of aluminium sulphates (E 520 to 523) and sodium aluminium phosphate (E 541))
- Flagged for young children. Set only where EFSA’s own exposure assessment shows toddlers or children exceeding or approaching the ADI, or where a regulator used explicitly child-specific language. For a child under 6 it moves up one class, to high risk.
- Where you meet it. None of the 10,000 packaged foods scanned most on Open Food Facts list it. Nine in ten of those foods are sold in Europe (counted 26 Sep 2026).
- 4 citations from EFSA, EU law and the FDA, each one below.
What Aluminium ammonium sulphate does to a score
A packaged food's additive subscore starts at 100 and loses points for each additive on the label; that subscore is a third of the final score. Aluminium ammonium sulphate takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100), and a child under 6 sees it one class higher again. Scan the pack in Sito and the score you get is the one for your own child's age, with this additive named in the reasons. How we score has the whole method.
See what is in your own cupboard
Scan a packaged food and Sito names the additives in it, then scores the product out of 100 for your child's age.
What the sources found
Every classification in our table comes from the citations below, and nothing else. Each finding is our one-line summary of what the source concluded, with the source and reference beside it.
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EFSA
Journal 2018;16(7):5372 — doi:10.2903/j.efsa.2018.5372, Re-evaluation of aluminium sulphates (E 520–523) and sodium aluminium phosphate (E 541)
Aluminium sulphates E 520–523 of no safety concern at current EU authorised uses (niche exposure); no genotoxicity or carcinogenicity concern; P95 aluminium exposure up to 0.88 mg/kg bw/day in toddlers and children flagged as highly uncertain. -
EU law
Commission Regulation (EU) No 380/2012, EUR-Lex CELEX:32012R0380
Aluminium additive levels cut across the board for consumer protection; the recitals rely on EFSA's TWI of 1 mg Al/kg bw/week being 'generally exceeded for high consumers, especially children'. -
EFSA
Journal 2008;6(7):754 — Safety of aluminium from dietary intake
TWI of 1 mg aluminium/kg bw per week; dietary exposure exceeds it for a significant part of the European population, with children the group of concern. -
FDA
21 CFR §182.1127 (aluminum ammonium sulfate, GRAS)
'This substance is generally recognized as safe when used in accordance with good manufacturing practice.' CAS 7784-26-1; FDA technical effects leavening agent, pH control agent, processing aid, surface-finishing agent.
Why this class
IARC Group 2B; or an EFSA re-evaluation that flagged genotoxicity data gaps, found safety could not be assessed on the available data, or cut the ADI citing child exposure; or an EU harmonised classification of the substance as a reproductive or developmental hazard; or an EU withdrawal of one authorised food use while others remain; or an OEHHA/Proposition 65 listing; or membership of the Southampton-six colourants.
Our confidence in this row's classification is medium. Medium or low does not mean the evidence is weak; it means something about the row is still being pinned down, usually a regulatory status confirmed from one source rather than two.
Questions parents ask
Is Aluminium ammonium sulphate (E523) safe for kids?
Moderate risk. In Sito it takes 15 points off the additive subscore, a third of a product's score (about 5 of the 100). It is flagged for young children, so for a child under 6 it moves up one class, to high risk: 30 points off the additive subscore. The finding we rely on: Aluminium sulphates E 520 to 523 of no safety concern at current EU authorised uses (niche exposure); no genotoxicity or carcinogenicity concern; P95 aluminium exposure up to 0.88 mg/kg bw/day in toddlers and children flagged as highly uncertain (EFSA Journal 2018;16(7):5372, doi:10.2903/j.efsa.2018.5372, Re-evaluation of aluminium sulphates (E 520 to 523) and sodium aluminium phosphate (E 541)).
What is E523?
E523 is the E number for Aluminium ammonium sulphate, an acidity regulator. Open Food Facts tags it en:e523.
Next to it on the label
The E numbers either side of E523 in our table, then the closest acidity regulators by number.
- Calcium sulphate (E516), no risk identified
- Ammonium sulphate (E517), no risk identified
- Aluminium sulphate (E520), moderate risk, flagged for young children
- Aluminium sodium sulphate (E521), moderate risk, flagged for young children
- Aluminium potassium sulphate (E522), moderate risk, flagged for young children
- Sodium hydroxide (E524), no risk identified