Sodium (1i535) and potassium ferrocyanide (1i536) in feed salt authorised until 4 May 2035: 80 mg ferrocyanide ion/kg NaCl for turkeys, pigs, ruminants and others, 60 mg for all other species; determination by spectrophotometry at 700 nm, characterisation by the JECFA monograph
Commission Implementing Regulation (EU) 2025/708, published on 14 April 2025, following a re-evaluation authorises sodium ferrocyanide and potassium ferrocyanide as technological additives (anticaking agents) for all animal species — only in sodium chloride — and repeals Regulation (EC) No 1810/2005, which had authorised them without a time limit. In opinions of 21 March 2023 and 4 June 2024 EFSA found them safe for animals, consumers and the environment; at first it could not conclude on chickens for fattening and other species, which was resolved by a limit of 60 mg/kg salt. The additive and premixtures labelled before 4 November 2025, feed for food-producing animals labelled before 4 May 2026 and for other animals before 4 May 2027 may be used until stocks are exhausted.
- Annex: sodium ferrocyanide Na₄[Fe(CN)₆]·10H₂O (CAS 13601-19-9) and potassium ferrocyanide K₄[Fe(CN)₆]·3H₂O (CAS 14459-95-1), each ≥ 99 %, from chemical synthesis; moisture ≤ 1 %, water-insoluble matter ≤ 0.03 %, chloride ≤ 0.2 %, sulfate ≤ 0.1 %, free cyanide and ferricyanide not detectable. Methods: characterisation of the additive — FAO JECFA monograph “Calcium, potassium and sodium ferrocyanides”; ferrocyanide in sodium chloride — spectrophotometry at 700 nm. At most 80 mg ferrocyanide ion/kg NaCl for turkeys, laying hens, minor poultry for laying or breeding, pigs, ruminants, camelids, rabbits, equines, fish, dogs and cats; 60 mg/kg for all other species.
- Label and user safety (annex): “… ferrocyanide must not be mixed with strong acids” (pKa < −2 in water); the directions for use must state storage conditions and stability to heat treatment. If procedures are not sufficient, the additive and premixtures are used with skin and respiratory protection. EFSA: both are not irritant to skin and eyes and not skin sensitisers, but sodium ferrocyanide is considered a skin and respiratory sensitiser because of nickel (< 0.25–5.58 mg/kg in four batches); for the potassium salt inhalation exposure could not be assessed.
- Batch analyses (EFSA 2023): sodium salt — nine batches, on average 101.2 % (99.55–104), moisture 0.10 %, chloride 0.07 %, sulfate 0.05 %; dioxins 1.10 ng WHO-PCDD/F-TEQ/kg; Stauber-Heubach dusting potential on average 1026 mg/m³ (505–1505); identity confirmed by IR. Potassium salt — five batches, 99.61 % (99.56–99.70), dusting potential 40 mg/m³ (15–60); no data on mercury. Cyanide and ferricyanide not detectable in five batches of each salt.
- Toxicology (EFSA): group ADI for sodium, potassium and calcium ferrocyanides 0.03 mg/kg bw per day expressed as ferrocyanide ion (ANS Panel 2018, from a NOAEL of 4.4 mg/kg bw per day in male rats); the earlier temporary JECFA ADI was 0–0.025 mg/kg bw per day. In the first opinion at 80 mg/kg salt there was no margin of safety for chickens for fattening and poultry other than turkeys; in the 2024 opinion the applicant proposed 60 mg/kg for them and EFSA found this content safe. The corrigendum of 27 April 2026 concerns only the Portuguese version.