E541i - Acid sodium aluminium phosphate
What it is and how it is used
Acidic sodium aluminium phosphate — SALP to bakers — is a white powder made by reacting aluminium hydroxide, phosphoric acid and sodium salts. Great Britain authorises only the acidic form under E 541; the basic form used elsewhere as a cheese emulsifier is not on the list.
It exists to solve a specific baking problem. Most raising acids react the moment they meet water and bicarbonate, so a batter starts losing gas before it reaches the oven. SALP is slow-acting and heat-triggered: it holds back most of its reaction until the oven, which is why it is the raising acid of choice for industrial cake mixes, self-raising flour blends and refrigerated dough.
Foods commonly containing it
Fine bakery wares — sponge cakes, muffins, scone and cake mixes — and self-raising flour blends. Its GB authorisation is narrow: fine bakery wares only.
Safety summary
Sodium aluminium phosphate, acidic, is authorised in Great Britain as E 541, restricted to fine bakery wares.
The health-based reference value here is not a phosphate ADI but an aluminium one. EFSA set a tolerable weekly intake of 1 mg aluminium per kg of body weight per week in 2008 — a sharp reduction from the earlier JECFA figure of 7 mg — and confirmed it when re-evaluating the aluminium sulphates and E 541 in 2018. Aluminium accumulates in the body, which is why the reference value is weekly rather than daily.
Known concerns
EFSA's 2018 re-evaluation put mean aluminium exposure from E 520–523 and E 541 at up to 0.21 mg/kg bw/day in children. Aluminium also arrives from other additives, cookware and drinking water, so the additive contribution is only part of a cumulative total measured against a weekly limit.