Potassium sorbate
A preservative that stops mould and yeast growing. Found in cheese, wine, soft drinks, baked goods, and dried fruit.
At food-relevant doses, potassium sorbate alters gut bacteria composition in animal studies. When it appears alongside nitrite preservatives in processed meat, the two can react under stomach conditions to form mutagenic compounds, though the real-world significance in food is not yet fully established by regulators.
What is it?
Potassium sorbate is the potassium salt of sorbic acid, a straight-chain unsaturated fatty acid that occurs naturally in some berries. As a food additive it is produced synthetically and appears as a white crystalline powder, odourless and nearly tasteless. It dissolves easily in water and, once in solution, releases sorbic acid as the active antimicrobial agent.
What does it do?
In water-based food environments with a pH below about 6.5, potassium sorbate releases sorbic acid. Sorbic acid is lipid-soluble and passes through the cell membranes of moulds, yeasts, and certain bacteria. Once inside the microbial cell it interferes with the enzymes responsible for cellular respiration, particularly those involved in hydrogen transport, blocking the microorganism from generating energy and preventing it from reproducing. It is more effective against moulds and yeasts than against bacteria, and its potency falls off as pH rises toward neutral.
Where you will see it
Potassium sorbate is used widely across UK food categories. Common products include processed and ripened cheeses (including cottage cheese and cream cheese), yogurt and fermented dairy desserts, wine and cider (to prevent refermentation after bottling), soft drinks and fruit juices, baked goods such as cakes and pastries, dried and glacé fruits, margarines, dips and dressings, and some confectionery coatings. On a UK ingredient label it appears as potassium sorbate or E202.
What the science says
Gut bacteria: animal studies signal changes at food-relevant doses
Studies in mice given potassium sorbate at doses intended to mirror human dietary exposure found measurable shifts in gut bacterial composition, with the potassium sorbate group showing notably lower microbial diversity than controls. A 2024 mouse study found liver inflammation markers (including elevated interleukin-1 beta) during exposure, which reduced after a washout period. These are animal findings. No direct evidence that the same effects occur in people eating foods containing the additive at typical levels has been established, and the 2021 study authors noted no 'major gut dysbiosis'.
Mice given potassium sorbate at doses calibrated to human dietary exposure levels showed the lowest gut microbial diversity of all preservatives tested, with increased Parabacteroides and Adlercreutzia and reduced Proteobacteria.
Mice fed potassium sorbate for ten weeks showed inflammatory cell infiltration in the liver and raised serum interleukin-1 beta; both markers returned toward baseline after a five-week washout period.
Potassium sorbate at FDA-recommended concentrations inhibited the growth of Enterococcus faecalis, a common human gut microbiome species, by 43% during the exponential growth phase.
Reaction with nitrite preservatives: mutagenic compounds can form
When sorbic acid or potassium sorbate meets nitrite preservatives (such as sodium nitrite, E250, used in cured and processed meats) under acidic conditions similar to those in the stomach, mutagenic compounds including 1,4-dinitro-2-methylpyrrole can form. EFSA has recommended further research on the real-world formation of these compounds during food processing and storage, but as of its 2019 review no industry-submitted data on measured levels in actual food products had been provided. The regulatory gap means the risk under realistic conditions has not been fully assessed.
Sorbic acid and sodium nitrite react under acidic conditions (pH 3.5 to 4.2) to form 1,4-dinitro-2-methylpyrrole and ethylnitrolic acid, both of which showed direct mutagenic activity in laboratory assays.
EFSA noted that potassium sorbate is co-present with nitrite preservatives in a large number of processed food products and recommended that future research examine the formation of reaction products of toxicological concern under realistic food processing and storage conditions.
Reproductive and developmental toxicity: earlier concern resolved by follow-up study
EFSA's 2015 re-evaluation found a worrying signal in a two-generation rat study: shorter anogenital distance in male offspring at mid and high doses, a marker sometimes associated with hormonal disruption. Because of this, EFSA set only a temporary, precautionary ADI of 3mg/kg bodyweight per day rather than a full ADI. A purpose-designed follow-up study was then commissioned. EFSA reviewed this in 2019 and concluded the earlier finding was not confirmed; the temporary precautionary ADI was replaced with a full ADI of 11mg/kg bodyweight per day.
A two-generation rat study found decreased anogenital distance in male F2 pups at mid and high doses of sorbic acid, prompting EFSA to establish a temporary group ADI of 3mg sorbic acid/kg bodyweight per day pending further data.
An extended one-generation reproductive toxicity study did not reproduce the anogenital-distance effect; EFSA concluded the earlier finding was not relevant and established a full group ADI of 11mg sorbic acid/kg bodyweight per day. Genotoxicity was not established in either evaluation.
Skin and contact sensitivity
Potassium sorbate and sorbic acid are classified as rare skin sensitisers. A 2021 clinical study found that contact allergy from these preservatives in topical pharmaceuticals and medical devices is likely underestimated. This concern relates to skin contact, not food consumption. Food-route sensitisation has been reported anecdotally but robust clinical evidence for allergy triggered by ingestion is limited.
A review of 17 confirmed allergy cases found sorbic acid and potassium sorbate caused allergic contact dermatitis in patients using topical pharmaceutical products and medical devices; the authors concluded prevalence was probably underestimated.
Where it stands with the regulators
Who should be careful
People with a confirmed sensitisation to sorbic acid or potassium sorbate should check labels for 'potassium sorbate' or 'E202'. Those who react to sorbic acid will typically also react to potassium sorbate. People eating large amounts of processed and cured meats that contain both potassium sorbate and nitrite preservatives (look for E250, E251, E252, or 'sodium nitrite' alongside E202 or 'potassium sorbate') may wish to note EFSA's unresolved question about their co-use, though regulators have not issued a specific avoidance instruction.
The honest read
Potassium sorbate is one of the longest-established food preservatives, in use since the 1950s, and its basic toxicology is well characterised. The two most significant live questions are the gut microbiome studies and the nitrite co-use issue. The gut studies used food-relevant doses in animals and found real changes in bacterial composition and in one study, inflammation markers, but the research has not been replicated in humans and the long-term health meaning is unknown. The nitrite question is more specific: lab chemistry shows mutagenic products can form when the two preservatives meet in acidic conditions, and EFSA's own 2019 review noted the gap in real-world formation data and called for more research. Neither question has reached the threshold where a regulator has restricted its use, but neither has been closed out. The reproductive toxicity concern that prompted a temporary ADI in 2015 was resolved by a dedicated follow-up study in 2019.
Related additives
Common questions
Is E202 banned in the UK?
No. Potassium sorbate is an approved food additive in the UK and has been permitted across a wide range of food categories under UK food law, which assimilated EU Regulation 1333/2008 after Brexit. It is also permitted across the EU, the US (where the FDA classifies it as GRAS), and most other major markets.
Can potassium sorbate react with other preservatives in the same food?
In laboratory conditions, sorbic acid and nitrite preservatives react under stomach-like acidity to form compounds that showed mutagenic activity in cell tests. EFSA noted in 2019 that many processed and cured meat products contain both preservatives together and called for data on whether these compounds actually form in food under realistic conditions. No such data has been submitted to regulators, so the question has not been resolved. Regulators have not issued a restriction on co-use.
What foods contain E202?
In the UK you will find potassium sorbate most commonly in processed cheeses, cream cheese, yogurt, wine, cider, soft drinks, baked goods such as cakes and croissants, dried and glacé fruits, margarines, and dips. It is also used in some personal care products and cosmetics. On the label it appears as 'potassium sorbate' or 'E202'.
Is E202 vegan?
Yes. Potassium sorbate is synthetically produced and contains no animal-derived ingredients. It is suitable for vegans and vegetarians.
Sources
- EFSA FAF Panel opinion on the follow-up re-evaluation of sorbic acid (E200) and potassium sorbate (E202), EFSA Journal 2019;17(3):e05625
- EFSA FAF Panel opinion, PubMed Central full text (PMC7009143)
- EFSA ANS Panel, Scientific Opinion on the re-evaluation of sorbic acid (E200), potassium sorbate (E202) and calcium sorbate (E203) as food additives, EFSA Journal 2015;13(6):4144
- UK Food Standards Agency: Approved additives and E numbers
- Louca et al., Distinct Gut Microbiota Signatures in Mice Treated with Commonly Used Food Preservatives, Microorganisms 2021;9(11):2311
- Effects of potassium sorbate on systemic inflammation and gut microbiota in normal mice, Food and Chemical Toxicology 2024
- Dendooven et al., Allergic contact dermatitis from potassium sorbate and sorbic acid in topical pharmaceuticals and medical devices, Contact Dermatitis 2021
- Hartman, Review: putative mutagens and carcinogens in foods. II: sorbate and sorbate-nitrite interactions, Environmental Mutagenesis 1983;5:111-119
- Sorbate-nitrite reactions in meat products, Food Research International 1999
- European Commission authorization of sorbic acid and potassium sorbate in non-heat-treated vegetable mousses, Food Compliance International 2024
- IARC Monographs Volume 10: Parasorbic acid (Group 3, 1976/Supplement 7 1987) - inchem.org
Aaron Keen is the founder of NutraSafe. He researches and writes every additive entry himself, from the primary sources. About the research →
This is a guide, not medical advice. If an additive affects you, speak to your GP or a dietitian.
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