Potassium aluminium silicate (E555)

Potassium aluminium silicate is the additive the food industry lists as E555. 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).

What Potassium aluminium silicate 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. Potassium aluminium silicate 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.

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.

• EFSA Journal 2020;18(6):6152 — doi:10.2903/j.efsa.2020.6152, Re-evaluation of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) as food additives
  'Considering that only very limited toxicological data and insufficient information on the physicochemical characterisation of both food additives were available, the Panel concluded that the safety of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) could not be assessed.' For E 555 specifically the Panel considered it 'is not being used as a carrier, but as an inseparable component of potassium aluminium silicate-based pearlescent pigments', and calculated a theoretical regulatory maximum exposure as carrier for E 171 and E 172 that 'could theoretically far exceed the TWI' — no age-group-specific exposure estimate was produced for E 555.
• EFSA Journal 2008;6(7):754 — Safety of aluminium from dietary intake
  TWI of 1 mg aluminium/kg bw per week; dietary exposure exceeds the TWI in a significant part of the European population, children in particular.
• EU law Commission Regulation (EU) No 380/2012, EUR-Lex CELEX:32012R0380
  Cut permitted levels for aluminium-containing additives for consumer protection, citing EFSA's finding that the aluminium TWI 'is generally exceeded for high consumers, especially children'.
• FDA 21 CFR Part 182 Subpart C enumerated in full (six anticaking sections, none of them potassium aluminum silicate); 21 CFR §73.350 (mica-based pearlescent pigments), incorporating the identity spec at §73.1496(a)(1)
  No US anticaking authorisation located for potassium aluminum silicate. It appears in US food law only as the mica substrate of a titanium-dioxide-coated pearlescent colour additive permitted under §73.350 at ≤1.25% in cereals, confections and frostings, gelatin desserts, candies, supplement tablets and chewing gum.

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 Potassium aluminium silicate (E555) 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: 'Considering that only very limited toxicological data and insufficient information on the physicochemical characterisation of both food additives were available, the Panel concluded that the safety of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) could not be assessed.' For E 555 specifically the Panel considered it 'is not being used as a carrier, but as an inseparable component of potassium aluminium silicate-based pearlescent pigments', and calculated a theoretical regulatory maximum exposure as carrier for E 171 and E 172 that 'could theoretically far exceed the TWI', no age-group-specific exposure estimate was produced for E 555 (EFSA Journal 2020;18(6):6152, doi:10.2903/j.efsa.2020.6152, Re-evaluation of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) as food additives).

What is E555?

E555 is the E number for Potassium aluminium silicate, an additive. Open Food Facts tags it en:e555.

Next to it on the label

The E numbers either side of E555 in our table, then the closest additives of the same kind by number.

• Calcium ferrocyanide (E538), no risk identified
• Silicon dioxide (E551), no risk identified
• Calcium silicate (E552), moderate risk
• Magnesium silicates / talc (E553), moderate risk
• Sodium aluminium silicate (E554), high risk, flagged for young children
• Fatty acids (E570), no risk identified