E535 · Sodium ferrocyanide
- WHO
- Safe
- FDA
- Safe
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E535?
Sodium ferrocyanide is an anticaking agent added to table salt and some road-de-icing salt to keep it free-flowing. Despite containing the word 'cyanide,' the compound holds cyanide tightly bound to iron and does not release it under normal food conditions; EFSA and the FDA consider it safe at the low levels permitted in salt. Only trace amounts break down to release cyanide, and only under extreme conditions like strong acid or high heat well beyond normal cooking.
Also appears on labels as: Sodium ferrocyanide, Sodium hexacyanoferrate(II), Na4[Fe(CN)6], E535, E 535, E-535, INS 535, Food additive E535, Anti-caking agent E535, Sodium ferrocyanide food grade, Ferrocyanure de sodium, Ferrocyanuro de sodio.
What the evidence says
- Considered safe at permitted use levels; EFSA has set an acceptable daily intake and found no toxicity concern from normal dietary use.
- Theoretical cyanide release requires conditions (strong acid, high heat) not typically encountered in food preparation or the body.
Research behind the verdict
- Sodium Ferrocyanide: Anti-caking Agent Safety and Regulatory Assessment — EFSA Panel on Food Additives and Flavourings, EFSA Journal - Ferrocyanides Assessment (2018). A detailed safety evaluation of sodium ferrocyanide (E535) examining its use as an anti-caking agent in salt and other crystalline products. The research confirmed that sodium ferrocyanide presents acceptable safety margins when used according to strict regulatory guidelines and approved usage levels. The study noted its effectiveness in preventing clumping in table salt while emphasizing the importance of adherence to maximum permitted levels. The assessment supports its limited use in specific applications with established regulatory controls.[safe_in_moderation]
Frequently asked questions
Is E535 safe?
Our overall verdict for E535 (Sodium ferrocyanide) is “Safe”, based on the most cautious of the major regulators’ positions — FDA: safe; WHO: safe; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E535 vegan, halal or gluten-free?
According to our ingredient data for Sodium ferrocyanide — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E535 and why is it used?
Sodium ferrocyanide is an anticaking agent added to table salt and some road-de-icing salt to keep it free-flowing. Despite containing the word 'cyanide,' the compound holds cyanide tightly bound to iron and does not release it under normal food conditions; EFSA and the FDA consider it safe at the low levels permitted in salt. Only trace amounts break down to release cyanide, and only under extreme conditions like strong acid or high heat well beyond normal cooking.
Does E535 contain allergens?
No known allergens are recorded for Sodium ferrocyanide.
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.