Ferrous lactate
An iron salt used in a handful of speciality foods to keep olives looking dark and to add iron to fortified products.
What is it?
Ferrous lactate is the iron(II) salt of lactic acid. It forms as a pale greenish crystalline powder and dissolves readily in water. Iron is the mineral component; lactic acid is the same organic acid produced during fermentation and found naturally in yoghurt and pickles.
What does it do?
As a food additive its main job is colour retention. When added to treated black or dark green olives it reacts with polyphenols in the fruit to fix a stable dark colour, preventing the olives from turning brown or fading after processing. It also has a mild acidifying effect. Separately, when used as a nutrient rather than an additive, it supplies a bioavailable form of dietary iron for fortification of foods such as infant formula and breakfast cereals.
Where you will see it
Primarily in ready-to-eat black olives sold in tins and jars, where it is used alongside a heat treatment process. Also authorised in certain speciality preparations such as Albatrellus ovinus mushroom used in Swedish liver pates under a 2019 amendment. When used as an additive it will appear on a label as 'ferrous lactate' or 'E585'. When used purely for iron fortification it may appear as 'iron (as ferrous lactate)' in the nutritional fortification declaration rather than the additive list.
What the science says
Iron overload risk at typical dietary exposure
The amount of E585 present in foods as an additive is very small relative to daily iron intake from food as a whole. At permitted use levels in olives, the contribution to total iron intake is negligible for most people. Iron overload from food-additive sources at these levels is not a recognised concern for the general population. People with hereditary haemochromatosis, a genetic condition causing the body to absorb too much iron, are advised by clinicians to watch all dietary iron sources, including supplements and fortified foods.
EFSA's Panel on Food Additives and Nutrient Sources (ANS Panel) evaluated ferrous lactate as a nutrient source and concluded the amount supplied as a food additive in permitted uses does not raise intake concerns for the general population.
People with hereditary haemochromatosis accumulate excess iron from all dietary sources; clinical guidance advises limiting iron-fortified and iron-added foods as part of broader dietary management.
Colour-fixing mechanism in olives
Black olives prepared by lye (alkaline) treatment lose their natural pigment and turn green or brown. Ferrous lactate is applied to fix the colour by binding iron ions to the olive's phenolic compounds, producing stable iron-polyphenol complexes that appear black. The process is well understood and the end product contains only trace residues of the iron salt itself.
The use of ferrous lactate and ferrous gluconate for colour fixation in treated black olives is a long-established technology reviewed and authorised under EU food additive legislation.
Where it stands with the regulators
Who should be careful
People with hereditary haemochromatosis or other iron-overload conditions are advised by their clinician to track all added-iron sources in their diet. Look for 'ferrous lactate', 'E585', or 'iron (as ferrous lactate)' on the label.
The honest read
E585 is a narrowly used additive: it turns up mainly in tinned or jarred black olives and a small number of specialist liver pate products. The science behind it is straightforward iron chemistry, not a novel compound. No active regulatory concern has been raised about intake at the levels found in these foods. For most people it is simply a trace iron salt encountered occasionally. The only group with a genuine reason to pay attention is people diagnosed with iron-overload conditions, who are typically already monitoring all dietary iron under medical advice.
Related additives
Common questions
Is E585 banned in the UK?
No. Ferrous lactate is on the UK FSA approved-additives list and is authorised for use in specified foods including thermally processed black olives. The authorisation was confirmed when the UK retained EU food additive rules at the end of 2020.
Why is it in olives?
Many commercially prepared black olives are made by treating green olives with an alkaline lye solution, which removes bitterness but destroys the natural colour. Ferrous lactate is then used to fix a stable black colour by binding with the olive's natural phenolic compounds. Without it the olives would be an unappetising grey-brown.
What foods contain E585?
Primarily tinned and jarred black olives. It is also authorised in preparations of the mushroom Albatrellus ovinus used in certain Swedish liver pates. When ferrous lactate is added purely for iron fortification in infant formula or breakfast cereals it does not carry an E number on the label and appears instead in the nutrition declaration.
Is E585 vegan?
Yes. Ferrous lactate is produced synthetically from lactic acid and iron salts. The lactic acid used in food-grade production is typically from fermentation of plant-based carbohydrates, not from dairy or animal sources. It does not contain any animal-derived ingredients.
Sources
- UK FSA regulated products database: E585 ferrous lactate
- EU Regulation (EC) No 1333/2008 on food additives
- Commission Regulation (EU) 2019/891 amending Annexes I and II to Regulation (EC) No 1333/2008 regarding use of ferrous lactate
- Iron(II) lactate, Wikipedia
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