Aluminium Potassium Sulfate
The short version
Potash alum — the classical pickle-firmer and double-acting-baking-powder acid, now restricted in EU.
It's permitted and generally considered safe, but there are a few reasons to be mindful — like sensitivities in some people, debated studies, or intake limits. The Safety section below explains the specifics.
Safety profile
No ADI is used for aluminium compounds; they are assessed against a weekly limit. EFSA (2008) set a tolerable weekly intake (TWI) of 1 mg aluminium/kg body weight for all aluminium compounds in food, including additives, and JECFA (2011) set a provisional tolerable weekly intake of 2 mg/kg body weight. EFSA's 2018 re-evaluation found aluminium sulphates (E 520–523) of no safety concern at the current authorised uses and use levels. Soluble aluminium forms (like alum) contribute more to absorbed aluminium than metallic or insoluble forms — relevant under EFSA's lowered tolerable weekly intake for aluminium.
Sources
- EFSA ANS Panel — Re-evaluation of aluminium sulphates (E 520–523) and sodium aluminium phosphate (E 541) as food additives, EFSA Journal 2018;16(7):5372, doi:10.2903/j.efsa.2018.5372 — EFSA, 2018. Safety: no safety concern at current authorised uses; EFSA 2008 TWI 1 mg Al/kg bw applies to all aluminium compounds
- Commission Regulation (EU) No 380/2012 — conditions of use and use levels for aluminium-containing food additives — EUR-Lex / European Union, 2012. EFSA lowered the aluminium TWI to 1 mg/kg bw/week; E 520–523 restricted to candied cherries from 1 Feb 2014
- JECFA database — Aluminium (all aluminium compounds), evaluation 2011 (74th meeting) — WHO / Joint FAO/WHO Expert Committee on Food Additives, 2011. Safety: JECFA PTWI 2 mg/kg bw for aluminium compounds (earlier ADIs withdrawn in 2006)
- 21 CFR 182.1129 — Aluminum potassium sulfate (GRAS) — eCFR / US FDA, 2026. US status: GRAS under good manufacturing practice, no specific categories
Checked against these sources on .
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