Yellow prussiate of soda
13601-19-9 · 5HT6X21AID · ADDITION AGENT 55 · E 535 · Ferrate(4), hexacyano, tetrasodium · Ferrate(4), hexakis(cyanoC), tetrasodium, (OC611) · Ferrate(4-), hexacyano-, tetrasodium · Ferrate(4-), hexakis(cyano-.kappa.C)-, sodium (1:4), (OC-6-11)- · Ferrate(4-), hexakis(cyano-.kappa.C)-, tetrasodium, (OC-6-11)- · Ferrate(4-), hexakis(cyano-C)-, tetrasodium · Ferrate(4-), hexakis(cyano-C)-, tetrasodium, (OC-6-11)- · Ferrate(4-), hexakis(cyano-kappaC)-, sodium (1:4), (OC-6-11)- · Ferrate(4-), hexakis(cyano-kappaC)-, tetrasodium, (OC-6-11)- · FERROCYANIDES · HEXACYANOFERRATE OF SODIUM · HSDB 742 · INS NO.535 · INS-535 · lambda2-iron(2+) ion tetrasodium hexakis(iminomethanide) · Natriumhexazyanoferrat(II) · Sodium ferrocyanide · Sodium ferrocyanide (Na4(Fe(CN)6)) · Sodium ferrocyanide, AldrichCPR · sodium hexacyanidoferrate(4-) · sodium hexacyanidoferrate(II) · Sodium hexacyanoferate(II) · Sodium hexacyanoferrate · sodium hexacyanoferrate(4-) · Sodium hexacyanoferrate(II) · Sodium hexacyanoferrate(II) decahydrate, 99% · Sodium prussiate yellow · Tetrasodium ferrocyanide · tetrasodium hexacyanidoferrate · Tetrasodium hexacyanoferrate · Tetrasodium hexacyanoferrate(4) · Tetrasodium hexacyanoferrate(4-) · tetrasodium hexakis(cyanido-kappaC)ferrate(4-) · tetrasodium;iron(2+);hexacyanide · Yellow prussiate of soda · Yellow prussiate of sodaSodium hexacyanoferrate · E535 · 535 · tetrasodium;iron(2+);hexacyanide · Sodium ferrocyanide · Yellow prussiate of soda · Ferocianură de sodiu · FEROKYANID SODNÝ · Ferrocianeto de sódio · Ferrocianuro di sodio · Ferrocianuro sódico · Ferrocyanure de sodium · Ferrokyanid sodný · Ferroċjanur tas-sodju · Hexakyanoželeznatan sodný · Naatriumferrotsüaniid · NAATRIUMHEKSATSÜANOFERRAAT(II) · natrijev ferocianid · Natrijev ferocijanid · Natrio ferocianidas · Natriumferrocyanid · Natriumferrosyanidi · Natriumhexacyanoferraat(II) · NÁTRIUM-FERRO-CIANID · Nátrium-vas(II)-cianid · Nātrija ferocianīds · Sodium ferrocyanide · Żelazocyjanek sodu · Σιδηροκυανιούχο νάτριο · Натриев фероцианидE number E535INS 535CAS 13601-19-9
Listed as an anticaking agent by Canada, Codex and the US.
Listed as anticaking agents (CA, US, Codex) · humectants (US) · formulation aids (US)
- Canada: Anticaking agent — Health Canada, List of Permitted Anticaking Agents (List 1)
- United States: Anticaking agent or free-flow agent — FDA, Substances Added to Food: YELLOW PRUSSIATE OF SODA
- Codex Alimentarius: Anticaking agent — CXS 192-1995 Table One, INS 535
- United States: Humectant — FDA, Substances Added to Food: YELLOW PRUSSIATE OF SODA
- United States: Formulation aid — FDA, Substances Added to Food: YELLOW PRUSSIATE OF SODA
Yellow prussiate of soda, or sodium ferrocyanide, is an anticaking agent used in table salt. As with the potassium form, the cyanide is bound to iron in a stable complex rather than present as free cyanide.
Where it is and isn’t permitted
| Jurisdiction | Status | Scope and limits | Citation |
|---|---|---|---|
| Australia and New Zealand | Permitted, with conditions | 1 food category highest permitted level 50 mg/kg total of sodium and potassium ferrocyanide. | Food Standards Code, Schedule 15, S15—5, item 12.1.1, INS 535retrieved 2026-10-17 |
| Canada | Permitted, with conditions | 2 permitted uses Show every permitted use
| Health Canadaand 1 further provisionretrieved 2026-10-17 |
| European Union | Permitted, with conditions | 2 food categories highest permitted level 20 mg/kg Permitted as a member of Ferrocyanides. ML = 20 mg/kg. Note 1: The additives may be added individually or in combination. Show every food category
| Regulation (EC) No 1333/2008, Annex II, as amended by (EU) No 1129/2011and 1 further provisionretrieved 2026-10-18 |
| Great Britain | Permitted, with conditions | 2 food categories highest permitted level 20 mg/kg or mg/l Authorised under E 535-538, Ferrocyanides. ML = 20. Note (1): The additives may be added individually or in combination. Note (57): The maximum level is expressed as anhydrous potassium ferrocyanide. Show every food category
| Assimilated Regulation (EC) No 1333/2008, Annex II (as at 28 June 2024), under E 535-538and 1 further provisionretrieved 2026-10-18 |
| Japan | Permitted, with conditions | Designated additive: Appended Table 1, item 356, フェロシアン化物（フェロシアン化カリウム（別名ヘキサシアノ鉄（Ⅱ）酸カリウム）、フェロシアン化カルシウム（別名ヘキサシアノ鉄（Ⅱ）酸カルシウム）及びフェロシアン化ナトリウム（別名ヘキサシアノ鉄（Ⅱ）酸ナトリウム）に限る。） (“Ferrocyanides (li …Designated additive: Appended Table 1, item 356, フェロシアン化物（フェロシアン化カリウム（別名ヘキサシアノ鉄（Ⅱ）酸カリウム）、フェロシアン化カルシウム（別名ヘキサシアノ鉄（Ⅱ）酸カルシウム）及びフェロシアン化ナトリウム（別名ヘキサシアノ鉄（Ⅱ）酸ナトリウム）に限る。） (“Ferrocyanides (limited to Potassium Ferrocyanide (Potassium Hexacyanoferrate(II)), Calcium Ferrocyanide (Calcium Hexacyanoferrate(II)), and Sodium Ferrocyanide (Sodium Hexacyanoferrate(II)))” in the unofficial English translation; listed member: Sodium Ferrocyanide (Sodium Hexacyanoferrate(II))). Standards for use — Specifications and Standards for Foods, Food Additives, etc. (MHW Notification No. 370 of 1959), Part II (Food Additives), F (Standards for use), entry フェロシアン化ナトリウム: (1) [may be used only in the foods stated] “フェロシアン化ナトリウムは、食塩以外の食品に使用してはならない。” (2) [sets maximum levels of use for the foods stated; sets a combined limit where it is used together with the additives stated] “フェロシアン化ナトリウムの使用量は、無水フェロシアン化ナトリウムとして、食塩1kgにつき0.020g以下でなければならない。ただし、フェロシアン化カリウム若しくはフェロシアン化カルシウムの1種又は2種と併用する場合にあっては、それぞれの使用量の和が無水フェロシアン化ナトリウムとして、食塩1kgにつき0.020g以下でなければならない。” The Japanese is the standard as published. There is no official English translation of the Notification; the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications for this additive, in the same Notification, are not imported and are not shown here; nor are the general rules in F 添加物一般, which apply to every additive. | Regulations for Enforcement of the Food Sanitation Act (MHW Ordinance No. 23 of 1948), Appended Table 1retrieved 2026-10-18 |
| South Korea | Permitted, with conditions | Designated food additive: Standards and Specifications for Food Additives, Part III, 1. …Designated food additive: Standards and Specifications for Food Additives, Part III, 1. 일반식품첨가물 (general food additives), 페로시안화나트륨 (“Sodium Ferrocyanide”, the English the Code prints beside it). Main use (주용도) of 페로시안화나트륨: 고결방지제. Standard for use (사용기준) of 페로시안화나트륨: (1) [may be used only for the purpose or in the food the sentence states; sets a limit on the amount used] “페로시안화나트륨은 식염(천일염 제외)에 한하여 사용하여야 한다. 페로시안화나트륨의 사용량은 페로시안이온으로서 식염 1kg에 대하여 0.010g 이하(페로시안화칼륨 또는 페로시안화칼슘과 병용할 때에는 각각의 사용량의 합계가 페로시안이온으로서 식염 1kg에 대하여 0.010g 이하)이어야 한다.” The Korean is the standard as published. There is no official English translation of the current Code (the English version on MFDS’s website is the 2020 edition and has no legal effect); the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications (Part IV) are not imported, nor are the general standards in Part II, which apply to every additive. | Standards and Specifications for Food Additives (식품첨가물의 기준 및 규격), MFDS Notification, Part III (Standards for use, by item)retrieved 2026-10-18 |
| United States | Permitted, with conditions | 21 CFR 172.490retrieved 2026-10-17 | |
| Codex Alimentarius | Permitted, with conditions | 3 food categories highest permitted level 20 mg/kg Show every food category and its notes
| CXS 192-1995 Table One, INS 535and 2 further provisionsretrieved 2026-09-07 |
How much is permitted
A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.
| Australia and New Zealand | 50 mg/kg | 1 numeric limit |
|---|---|---|
| Canada | — | 2 no quantity stated |
| European Union | 20 mg/kg | 2 numeric limit |
| Great Britain | 20 mg/kg | 2 numeric limit |
| Japan | — | 1 no quantity stated |
| South Korea | — | 1 no quantity stated |
| United States | — | 1 no quantity stated |
| Codex Alimentarius | 14 mg/kg – 20 mg/kg | 3 numeric limit |
What it is made from
Manufactured from hydrogen cyanide, iron salts and sodium hydroxide. Its traditional name comes from Prussian blue, the pigment made from the same iron-cyanide chemistry.
- Vegan
- Vegetarian
Compare other additives on the dietary indexes.
- CAS registry number
- 13601-19-9
- InChIKey
- GTSHREYGKSITGK-UHFFFAOYSA-N
- PubChem
- CID 26129
The two specifications, compared
The European Union sets identity and purity by regulation; JECFA publishes its own through FAO, advisory until a country adopts it. Both documents are below in full. These are the parameters each puts a number on.
| Parameter | European Union | JECFA |
|---|---|---|
| Assay | no less than 99 % | no less than 99 % |
| Lead | no more than 5 mg/kg | no more than 5 mg/kg |
| Arsenic | — | no more than 3 mg/kg |
The two documents state the same figures for every parameter compared here.
How the EU defines it
The legal specification an additive must meet to be sold as this E number in the EU — what it is, how it may be made, and the purity it must reach. From Commission Regulation (EU) No 231/2012.
E 535 Sodium ferrocyanide
Synonyms: Yellow prussiate of soda; Sodium hexacyanoferrate
Assay, identification and purity criteria
Description and assay
- Einecs
- 237-081-9
- Chemical name
- Sodium ferrocyanide
- Chemical formula
- Na₄Fe(CN)₆ · 10 H₂O
- Molecular weight
- 484,1
- Assay
- Content not less than 99,0 %
- Description
- Yellow crystals or crystalline powder
Identification
- Test for sodium
- Passes test
- Test for ferrocyanide
- Passes test
Purity criteria
- Free moisture
- Not more than 1,0 %
- Water insoluble matter
- Not more than 0,03 %
- Chloride
- Not more than 0,2 %
- Sulphate
- Not more than 0,1 %
- Free cyanide
- Not detectable
- Ferricyanide
- Not detectable
- Lead
- Not more than 5 mg/kg
How JECFA defines it
The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.
INS 535 Ferrocyanides of Calcium, Potassium and Sodium
Synonyms: Yellow prussiate of lime, potash or soda; hexacyanoferrate of calcium, potassium or sodium; INS No. Calcium salt 538, Potassium salt 536, Sodium salt 535
Assay, identification and purity criteria
Description and assay
- Specification history
- Prepared at the 17th JECFA (1973), published in FNP 4 (1978) and in FNP 52 (1992). Metals and arsenic specifications revised at the 57th JECFA (2001). An ADI of 0-0.025 mg/kg bw was established at the 18th JECFA (1974)
- Chemical names
- Calcium (or Potassium or Sodium) ferrocyanide, Calcium (or Potassium or Sodium) hexacyanoferrate (II)
- C.A.S. number
- 1327-39-5, Calcium salt 13943-58-3, Potassium salt 13601-19-9, Sodium salt
- Chemical formula
- Ca 2 Fe(CN) 6 · 12H 2 O K 4 Fe(CN) 6 · 3H 2 O Na 4 Fe(CN) 6 · 10H 2 O
- Formula weight
- Calcium salt 508.3 Potassium salt 422.4 Sodium salt 484.1
- Assay
- Not less than 99.0% of the respective ferrocyanide
- DESCRIPTION
- Yellow crystals or crystalline powder
- FUNCTIONAL USES
- Anticaking agent
- METHOD OF ASSAY
- Weigh 3 g of the sample to the nearest 0.1 mg and transfer into a 400-ml beaker. Dissolve in 225 ml of water, and add cautiously about 25 ml of sulfuric acid TS. Add, with stirring, 1 drop of orthophenanthroline TS, and titrate with 0.1 N ceric sulfate until the colour changes sharply from orange to pure yellow. Each ml of 0.1 N ceric sulfate is equivalent to 50.83 mg of Ca 2 Fe(CN) 6 · 12H 2 O; 42.24 mg of K 4 Fe(CN) 6 · 3H 2 O or 48.41 mg of Na 4 Fe(CN) 6 · 10H 2 O.
Identification
- Solubility (Vol. 4)
- Soluble in water; potassium and sodium salts are insoluble in ethanol
- Test for ferrocyanide
- To 10 ml of a 1% solution of the sample add 1 ml of ferric chloride TS. A dark blue precipitate is formed. (Retain the mixture for the Test for calcium).
- Test for calcium (Vol. 4)
- Passes test Test the mixture from the Test for ferrocyanide
- Test for potassium (Vol. 4)
- Passes test
- Test for sodium (Vol. 4)
- Passes test
Purity criteria
- Cyanide
- Not detectable Dissolve 10 mg of copper sulfate in a mixture of 8 ml of water and 2 ml of ammonia TS. Wet a strip of filter paper with this solution, and place the wet paper in a stream of hydrogen sulfide. When one drop of a 1% solution of the sample is placed on the brown reagent paper, a white circle should not be produced.
- Ferricyanide
- Not detectable Dissolve about 10 mg of the sample in 10 ml of water and place one drop of this solution on a spot plate. Add one drop of a 1% solution of lead nitrate, followed by a few drops of a solution prepared by saturating cold 2 N acetic acid with benzidine. No blue precipitate or blue coloration should appear.
- Arsenic (Vol. 4)
- Not more than 3 mg/kg (Method II)
- Lead (Vol. 4)
- Not more than 5mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”
Every name it appears under
69 recorded names. A label may use any of them.
E number
- E535
INS number
- 535
CAS registry number
- 13601-19-9
As it appears in regulation
- Sodium ferrocyanide
- Yellow prussiate of soda
Other names
- 5HT6X21AID
- ADDITION AGENT 55
- E 535
- Ferrate(4), hexacyano, tetrasodium
- Ferrate(4), hexakis(cyanoC), tetrasodium, (OC611)
- Ferrate(4-), hexacyano-, tetrasodium
- Ferrate(4-), hexakis(cyano-.kappa.C)-, sodium (1:4), (OC-6-11)-
- Ferrate(4-), hexakis(cyano-.kappa.C)-, tetrasodium, (OC-6-11)-
- Ferrate(4-), hexakis(cyano-C)-, tetrasodium
- Ferrate(4-), hexakis(cyano-C)-, tetrasodium, (OC-6-11)-
- Ferrate(4-), hexakis(cyano-kappaC)-, sodium (1:4), (OC-6-11)-
- Ferrate(4-), hexakis(cyano-kappaC)-, tetrasodium, (OC-6-11)-
- FERROCYANIDES
- HEXACYANOFERRATE OF SODIUM
- HSDB 742
- INS NO.535
- INS-535
- lambda2-iron(2+) ion tetrasodium hexakis(iminomethanide)
- Natriumhexazyanoferrat(II)
- Sodium ferrocyanide
- Sodium ferrocyanide (Na4(Fe(CN)6))
- Sodium ferrocyanide, AldrichCPR
- sodium hexacyanidoferrate(4-)
- sodium hexacyanidoferrate(II)
- Sodium hexacyanoferate(II)
- Sodium hexacyanoferrate
- sodium hexacyanoferrate(4-)
- Sodium hexacyanoferrate(II)
- Sodium hexacyanoferrate(II) decahydrate, 99%
- Sodium prussiate yellow
- Tetrasodium ferrocyanide
- tetrasodium hexacyanidoferrate
- Tetrasodium hexacyanoferrate
- Tetrasodium hexacyanoferrate(4)
- Tetrasodium hexacyanoferrate(4-)
- tetrasodium hexakis(cyanido-kappaC)ferrate(4-)
- tetrasodium;iron(2+);hexacyanide
- Yellow prussiate of soda
- Yellow prussiate of sodaSodium hexacyanoferrate
Systematic names
- tetrasodium;iron(2+);hexacyanide
Hazard reference values
The two committees set different figures. EFSA's acceptable daily intake is 0.03 mg/kg bw/day (2018); JECFA's is 0.025 mg/kg bw/day (1974). An acceptable daily intake is a reference value set by a committee, not a threshold above which harm begins. The lower figure is not a finding that the other body was wrong: the two work to different terms of reference, on their own timetables, and sometimes from different data. This site states both and chooses between them nowhere. See where the two committees differ.
Evidence and how bodies read it
What assessing bodies concluded
Each conclusion is paraphrased in the body's own framing, from the published opinion linked beneath it. Where bodies differ, both stand; this site does not adjudicate between them or add a view of its own.
EFSA 2018
The ANS Panel found no concern for genotoxicity or carcinogenicity for sodium, potassium and calcium ferrocyanide (E 535–E 538) and, based on kidney effects in a two-year rat study, established a group ADI of 0.03 mg/kg bw/day expressed as ferrocyanide ion. It concluded they are of no safety concern at the current authorised use as salt substitutes and use levels.
Common questions
Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.
- What is E 535?
- E 535 is Yellow prussiate of soda. Yellow prussiate of soda, or sodium ferrocyanide, is an anticaking agent used in table salt. As with the potassium form, the cyanide is bound to iron in a stable complex rather than present as free cyanide.
- What is Yellow prussiate of soda used for in food?
- It is listed as an anticaking agent — the role Canada, Codex and the US assign it. This page shows every function each regulator records, with the citation for each.
- Where is Yellow prussiate of soda permitted?
- Of the seven regulators this site reads, Australia and New Zealand, Canada, the EU, Great Britain, Japan, South Korea, the US and the Codex standard permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
- Is Yellow prussiate of soda vegan?
- Yes. Yellow prussiate of soda is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.
Sources for this page
- anz retrieved 2026-10-17
- ca retrieved 2026-10-17
- eu retrieved 2026-10-18
- gb retrieved 2026-10-18
- jp retrieved 2026-10-18
- kr retrieved 2026-10-18
- ecfr retrieved 2026-10-17
- gsfa retrieved 2026-09-07
- euspecs retrieved 2026-10-18
- jecfaspecs retrieved 2026-09-23
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