E-numbers / Preservatives / E237
also: Sodium methanoate · Formic acid sodium salt
The sodium salt of formic acid, historically used as a preservative. No longer a permitted food additive in the UK or EU.
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E237 is not authorised for use in UK or EU food.
Why it’s worth knowing. E237 is not authorised for use in UK or EU food. Finding it on a UK product label would indicate a compliance issue with current food law.
Sodium formate (sodium methanoate) is the sodium salt of formic acid, the simplest carboxylic acid. It is a white crystalline powder, naturally present in tiny amounts in some fruits and produced industrially by reacting sodium hydroxide with carbon monoxide under pressure.
Acts as a preservative by creating mildly acidic conditions and releasing formate ions that inhibit the growth of bacteria, moulds and yeasts. In the body, formate is metabolised primarily in the liver and excreted in urine. At very high concentrations it has a diuretic effect.
Historically listed for potential use in fruit juices, non-alcoholic drinks and preserved vegetables. Because E237 is not currently authorised in the UK or EU, you should not encounter it on a UK food label. If you do see 'sodium formate' or 'E237' on a label, that product may not comply with current UK food law.
The formates group (formic acid E236, sodium formate E237, calcium formate E238) were carried over from earlier European approved lists but were not included in the positive list (Annex II) of EU Regulation 1333/2008 when that regulation was finalised. The UK FSA approved-additives list, which reflects the assimilated version of that regulation, does not list E237. This means no food in the UK or EU is legally permitted to contain sodium formate as an intentionally added preservative.
E237 (sodium formate) does not appear in the UK Food Standards Agency's approved-additives list, indicating it is not an authorised food additive under UK food law.
Annex II of EU Regulation 1333/2008, which establishes the positive list of food additives permitted in food for sale to consumers, does not include sodium formate (E237), making it impermissible for use as a food additive across the EU.
Before the formates were excluded from the EU positive list, the former EU Scientific Committee on Food (SCF) set a group ADI for formic acid and its salts of 3 mg per kg of body weight per day. Formate is a normal, short-lived metabolite in human one-carbon metabolism and is cleared rapidly by the liver. At the concentrations proposed for food use, no adverse effects were identified in the historical safety data.
The former EU Scientific Committee on Food established a group acceptable daily intake of 3 mg/kg body weight per day for formic acid and its salts, including sodium formate, based on available animal and metabolic data.
Sodium formate is metabolised in the liver and excreted renally. High doses are diuretic. At concentrations within the historical ADI no adverse effects were described in available studies.
Sodium formate has separately been evaluated and authorised in the EU as a technological additive in animal feed, specifically as a preservative. This is governed by a different regulation from food additives and does not affect the human food additive status. EFSA published a positive opinion on sodium formate as a feed additive in 2020.
EFSA concluded that sodium formate is efficacious as a preservative technological additive in animal feed for all animal species.
No one should encounter E237 in a legally sold UK or EU food product. If you find 'sodium formate' or 'E237' on a food label, that product is using an ingredient not authorised under current UK food additive law.
E237 is genuinely obscure in the consumer food context because it has not been a permitted food additive in the EU or UK under modern food law. Historical glossary sites sometimes list it as 'approved' because they are reflecting older pre-2008 frameworks. The additive itself, sodium formate, is not especially hazardous at low concentrations based on the metabolic data that existed when it was reviewed, but that question is largely academic since it should not be present in any UK food sold today. The more relevant fact for a shopper is straightforward: it is not on the permitted list.
E237 (sodium formate) is not a permitted food additive in the UK. It does not appear on the UK Food Standards Agency's approved-additives list, which means food businesses cannot legally add it to food products sold in the UK.
Many E-number reference sites were written before EU Regulation 1333/2008 came into force and still reflect older, superseded approved-additives frameworks. When the EU established its current positive list (Annex II of Regulation 1333/2008), sodium formate was not included, so those older 'approved' listings are out of date.
Because E237 is not an authorised food additive in the UK or EU, no food product legally sold here should contain it as an intentional additive. Historically it was proposed for fruit juices, soft drinks and preserved vegetables, but it never became a common ingredient even when the regulatory position was less clear.
Sodium formate is produced from inorganic starting materials (sodium hydroxide and carbon monoxide) and contains no animal-derived ingredients, so it is suitable for vegans and vegetarians. However, this is largely a theoretical question since the additive is not permitted in UK or EU food.
Last reviewed: 20 June 2026
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