E-numbers / Preservatives / E212
also: Potassium salt of benzoic acid · INS 212
A preservative that stops mould and bacteria growing in acidic foods and drinks, closely related to sodium benzoate (E211).
Scan a barcode to check a food for potassium benzoate. NutraSafe Pro · £6.99/month · iPhone and Android
When E212 appears in a product that also contains vitamin C (ascorbic acid), the two can react to form benzene, an IARC Group 1 carcinogen.
UK supermarket foods that declare E212: 5 of the 43,325 we checked (under 0.1%)
Counted by its code or its name in the ingredient list.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. When E212 appears in a product that also contains vitamin C (ascorbic acid), the two can react to form benzene, an IARC Group 1 carcinogen. Children who regularly drink flavoured soft drinks preserved with benzoates may also exceed the daily intake level set by European regulators. People sensitive to aspirin or prone to asthma and urticaria may react to benzoate preservatives.
The potassium salt of benzoic acid. In food it behaves identically to sodium benzoate (E211) and calcium benzoate (E213), breaking down in the body to benzoic acid. It is more soluble in water than benzoic acid itself, which makes it practical for liquid foods.
Benzoate ions disrupt the internal pH regulation of microbial cells, preventing mould, yeast and many bacteria from growing. The effect is strongest below pH 4.5, which is why benzoate preservatives are concentrated in acidic products such as fizzy drinks, pickles and fruit-based condiments.
Most commonly in carbonated soft drinks and flavoured still drinks, fruit juices, pickles and pickled vegetables, olives, salad dressings, condiments and sauces, jams and fruit-based spreads, and some fruit-flavoured dairy products such as yogurt drinks. On a UK ingredient label it will appear as 'potassium benzoate' or 'E212'.
When benzoate preservatives meet ascorbic acid (vitamin C) in an acidic drink, a chemical reaction can produce benzene. Heat and light speed the reaction up. Benzene is classified by IARC as a Group 1 carcinogen, meaning it causes cancer in humans, with leukaemia the best-established outcome. The FDA tested around 200 beverages in 2006 and found that most contained no detectable benzene or levels below 5 parts per billion; four products exceeded the EPA drinking-water limit and were reformulated. UK FSA testing in 2008 found 99 per cent of 250 soft drinks within legal limits. The real-world risk depends on product formulation and storage, but the formation pathway is established chemistry.
Benzene is a Group 1 human carcinogen, sufficient evidence that it causes acute myeloid leukaemia; successive IARC Monograph evaluations from 1974 through to Volume 120 in 2018 have consistently upheld this classification.
The FDA found that benzoate salts combined with vitamin C in beverages can produce benzene; testing of around 200 beverages in 2006 found four products exceeded the EPA drinking-water guidance of 5 ppb, all of which were subsequently reformulated.
A UK FSA survey of 250 soft drinks in 2008 found that 99 per cent were within legal limits for benzoates; the survey confirmed the risk of benzene formation when both benzoate preservatives and ascorbic acid are present.
The EFSA panel that re-evaluated benzoate preservatives in 2016 set a group acceptable daily intake of 5mg per kilogram of body weight per day for the whole benzoate family (E210 to E213). It found that toddlers and children who regularly drink flavoured soft drinks, in what EFSA called a 'brand-loyal' pattern, exceed this intake level. When additional exposure from natural benzoic acid in fruits and vegetables is included, exceedance extended to the broader child population at higher consumption levels.
EFSA set a group ADI of 5mg/kg body weight per day for benzoic acid and its salts (E210-E213) and found that this ADI was exceeded in the brand-loyal scenario for toddlers and children who regularly consume flavoured drinks; when carry-over from processed fruit and vegetables is included, intake could rise two to threefold above the ADI.
The most cited study on this question is the McCann et al. 2007 Lancet trial from the University of Southampton. It found that mixes of synthetic food colours together with sodium benzoate increased hyperactivity scores in 3-year-old and 8 to 9-year-old children in the general population. EFSA reviewed the study and concluded it provided limited evidence of a small effect on activity and attention in some children, but noted that the results were not consistent across age groups or between the two additive mixtures tested. Critically, because the cocktails always contained both colours and benzoate, the role of the benzoate alone cannot be isolated from this study.
A randomised, double-blinded, placebo-controlled trial found that mixes of artificial food colours and sodium benzoate increased hyperactivity in 3-year-old and 8 to 9-year-old children in the general population.
EFSA's AFC Panel concluded the McCann 2007 study provided limited evidence of a small effect on activity and attention in some children, with results not consistent across age groups or between the two additive mixtures; EFSA could not confirm sodium benzoate as the causative agent given that colours were always present in the same mix.
Clinical provocation studies have found that a subset of people with aspirin hypersensitivity, asthma, or chronic urticaria also react to benzoate preservatives. Reactions documented include bronchoconstriction, skin rashes, and urticaria. The intolerance appears related to shared pharmacological mechanisms rather than true immune allergy. Prevalence estimates from provocation studies range from around 2 per cent in rhinitis patients to roughly 11 per cent in people with asthma.
Provocation with sulphur dioxide, sodium benzoate and tartrazine in orange drinks caused bronchoconstriction in a subset of asthma patients; benzoate sensitivity was documented as a distinct reaction pattern.
Oral provocation tests with aspirin, tartrazine and benzoic acid revealed intolerance to additives in 26.6 per cent of 620 patients tested; benzoate intolerance specifically ranged from 2.5 per cent in rhinitis patients to 11.5 per cent in asthma patients.
People with aspirin sensitivity, chronic asthma, or a history of urticaria from food additives may react to benzoate preservatives. Parents of young children may wish to limit flavoured drinks preserved with benzoates, as regular high intake can push toddlers and children above the regulatory daily limit. Look for 'potassium benzoate' or 'E212' in the ingredients. Where a drink also lists ascorbic acid or vitamin C, benzene formation is possible if the product is stored in heat or light.
There are two genuinely distinct concerns here, not one. The benzene risk is real chemistry: if a product contains both a benzoate and vitamin C, benzene can form. Most modern manufacturers have reformulated to avoid this combination, or manage storage conditions tightly, but the reaction pathway is not disputed. The hyperactivity link is murkier: the best-known trial always mixed benzoate with six synthetic colours, so the benzoate contribution cannot be isolated. EFSA called the evidence limited. The children's exposure question is the clearest regulatory concern: EFSA's own 2016 calculation found that toddlers drinking flavoured soft drinks in a predictable pattern exceed the intake level set by regulators. That finding has not resulted in a ban, but it stands on the record.
No. Potassium benzoate is an authorised food additive in the UK and EU, permitted in a range of acidic foods and drinks under assimilated EU Regulation 1333/2008.
Yes, under certain conditions. When potassium benzoate is present alongside ascorbic acid (vitamin C) in an acidic drink and the product is exposed to heat or light, a reaction can produce benzene. Benzene is a Group 1 carcinogen (causes cancer in humans) according to IARC. The FDA found that most commercially tested products contained no detectable benzene or levels below regulatory guidance, but four products in 2006 exceeded the limit and were reformulated. The risk depends on the specific formulation and how the product is stored.
Most commonly carbonated and flavoured soft drinks, fruit juices, pickles, olives, salad dressings, condiments, jams and some fruit-flavoured dairy products. On the label it appears as 'potassium benzoate' or 'E212'.
Yes. Potassium benzoate is a synthetic preservative derived from benzoic acid. It contains no animal-derived ingredients and is considered vegan.
Last reviewed: 20 June 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iPhone and Android
