E-numbers / Other additives / E534
also: Iron tartrate · iron(III) tartrate · complexation product of sodium tartrate and iron(III) chloride
An iron salt of tartaric acid used to stop salt and salt substitute granules clumping together in the packet.
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Ferric tartrate is the iron(III) salt of tartaric acid, a naturally occurring fruit acid.
Ferric tartrate is the iron(III) salt of tartaric acid, a naturally occurring fruit acid. It is a fine powder that coats the surface of salt granules, preventing them from absorbing moisture and sticking together. It carries both iron (a mineral) and tartrate (derived from grapes and wine production).
Acts as an anti-caking agent. The fine iron tartrate particles coat salt crystals and physically separate them, absorbing trace moisture before it can bridge crystals together. This keeps granulated salt free-flowing in humid conditions. It provides a small incidental source of iron but is not used as a supplement.
Found almost exclusively in table salt and low-sodium salt substitutes (potassium chloride blends). Likely products include low-salt and reduced-sodium table salts. On a UK label it appears as 'ferric tartrate' or 'E534' in the ingredients list.
Because E534 is used in very small amounts as an anti-caking agent in salt, the iron contributed to the diet is negligible compared with dietary iron from food. The quantity present per normal serving of salt is far below any level associated with iron toxicity. No specific toxicological concern has been raised for ferric tartrate at permitted food additive levels.
Commission Regulation (EU) 2015/1739 authorised iron tartrate as an anti-caking agent in salt and salt substitutes, indicating the European Food Safety Authority reviewed it and found the use acceptable at the levels proposed.
The tartrate portion is the same anion found in E334 (tartaric acid) and E335-E337 (sodium, potassium and calcium tartrates), which are long-established food additives used in baking, confectionery and beverages. EFSA reviewed the tartrate group in 2020 and set a group acceptable daily intake. At the tiny quantities used in salt as an anti-caking agent, tartrate intake from E534 is insignificant against this limit.
EFSA re-evaluated tartaric acid and tartrate salts (E334, E335, E336, E337, E354) in 2020 and established a group ADI of 240mg per kilogram of body weight per day, concluding no safety concern at authorised uses.
People managing iron overload conditions (such as haemochromatosis) should be aware that ferric tartrate contributes a small amount of iron, though at anti-caking quantities in salt this is very minor. People avoiding iron-fortified foods for medical reasons should check ingredient labels for 'ferric tartrate' or 'E534'.
E534 is a narrow-use additive found only in salt and salt substitutes. It has been in permitted use since 2015 following regulatory review. The science here covers an ordinary anti-caking agent with no identified hazard signal at food use levels. The tartrate component belongs to a well-established group of food acids reviewed by EFSA as recently as 2020.
No. Ferric tartrate is a permitted food additive in the UK, authorised under assimilated EU law for use as an anti-caking agent in salt and salt substitutes. It was added to the approved list by an EU amendment in 2015 and that permission carried over into UK law on EU exit.
It coats salt granules with a fine powder that stops moisture bridging between crystals. Without an anti-caking agent, salt can harden into clumps in humid conditions. E534 keeps granules free-flowing.
Its permitted use is limited to salt and salt substitutes. You are most likely to encounter it in low-sodium table salts or potassium chloride-based salt replacement products.
Yes. Ferric tartrate is synthesised from iron salts and tartaric acid (a plant-derived acid from grapes). It contains no animal-derived ingredients.
Last reviewed: 20 June 2026
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