Sodium ferrocyanide and related additives in salt
What it found
In this safety review, the amounts of ferrocyanides people take in from salt were far below the level the authors set as acceptable.
The authors say these additives raise no safety concern at the amounts currently used.
What they found
Studies in people
Amounts people take in
From salt, children and adolescents took in up to 0.009 mg per kg body weight per day in the highest scenario, and up to 0.003 mg per kg body weight per day in the refined scenario. The authors say these estimates are likely too high.
Absorption and build-up
Ferrocyanides are poorly absorbed from the gut, and they do not build up in the human body.
Animal and lab studies
Kidney effects in rats
In a 2-year rat study, the kidney was the organ affected. The authors identified 4.4 mg sodium ferrocyanide per kg body weight per day as the highest dose with no harmful effect on the kidney.
Damage to genes
The authors found no concern that ferrocyanides damage genes or cause cancer.
Pregnancy study
No reproductive studies were available, but a prenatal development study found no harmful effects at the highest dose tested, 1,000 mg sodium ferrocyanide per kg body weight per day.
Other findings
Acceptable daily intake
The authors set a group acceptable daily intake for sodium, potassium and calcium ferrocyanide of 0.03 mg per kg body weight per day, expressed as ferrocyanide ion. This replaces an older value.
What the authors conclude
“The Panel concluded that ferrocyanides (E 535–538) are of no safety concern at the current authorised use and use levels.”
Also in their conclusions
- They conclude that ferrocyanides (E 535-538) are of no safety concern at the current authorised use and use levels.
- They further conclude that the available data give reason to revise the ADI of 0.025 mg sodium ferrocyanide/kg bw per day to a group ADI for sodium, potassium and calcium ferrocyanide of 0.03 mg/kg bw per day expressed as ferrocyanide ion.
How it was done
The European Commission asked the authors to look again at the safety of these additives, which had been assessed before, and to check whether the amounts people take in from food are within safe limits.
The authors looked at existing studies on how ferrocyanides are absorbed, their toxicity in animals, and how much people take in from salt. They used salt intake data from urine studies to estimate how much ferrocyanide people consume.
What it can’t tell you
- The authors did not have reproductive studies, so they could not fully assess effects on reproduction.
- The exposure estimates are based on salt intake from urine studies and may not reflect actual intakes in all people.
The paper
- Title
- Re-evaluation of sodium ferrocyanide (E 535), potassium ferrocyanide (E 536) and calcium ferrocyanide (E 538) as food additives
- Type
- Scientific opinion of the European Food Safety Authority
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Younes M, Aggett P, et al (2018). Re-evaluation of sodium ferrocyanide (E 535), potassium ferrocyanide (E 536) and calcium ferrocyanide (E 538) as food additives. EFSA journal. European Food Safety Authority. doi:10.2903/j.efsa.2018.5374Free full textPubMed 32626000DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error