E-numbers / Preservatives / E228
also: Potassium bisulphite · Potassium bisulfite · INS 228
A sulphite preservative that stops wine, dried fruit and other foods spoiling and going brown. Must be declared on the label above a very low threshold.
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Grapes, Stabilisers (Potassium Polyaspartate, Acacia Gum), Preservative (Potassium Bisulphite), Antioxidant (Ascorbic Acid), Packaging Gas (Nitrogen).
Sulphites trigger asthma attacks, wheezing and severe allergic reactions in sensitive people, particularly those with asthma.
43
of the 43,325 UK supermarket foods we checked declare E228 in their ingredients
That is under 0.1%, counted by its code or its name.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. Sulphites trigger asthma attacks, wheezing and severe allergic reactions in sensitive people, particularly those with asthma. In 2022, the EU food safety authority withdrew sulphites' safe daily intake figure after animal studies pointed to nervous system effects at higher exposures.
Potassium hydrogen sulphite, also called potassium bisulphite, is an inorganic potassium salt of sulphurous acid. It belongs to the group of sulphite additives (E220 to E228), all of which release sulphur dioxide when dissolved in food or drink.
It releases sulphur dioxide, which kills or suppresses bacteria, moulds and yeasts. It also blocks the enzyme reactions that cause cut or dried produce to turn brown. In wine it prevents oxidation and unwanted fermentation. All eight sulphite additives (E220 to E228) are evaluated as a group because their active agent in food is the same sulphur dioxide.
Most commonly found in wine, cider and beer, where it prevents oxidation and microbial spoilage. Also used in dried fruits such as apricots, raisins and sultanas, dried or pre-cut potato products, fruit juices, vinegar, pickles, and some seafood products. On a UK label it will appear as 'potassium hydrogen sulphite', 'potassium bisulphite', 'E228', or simply as 'sulphites' or 'sulphur dioxide' in the allergen declaration.
A subset of people with asthma react to sulphites with wheezing, chest tightness and, in severe cases, life-threatening bronchospasm. Studies estimate that between 3% and 13% of asthmatic individuals are sulphite-sensitive, rising to around 20% in those who depend on steroid inhalers. The precise mechanism is not fully understood; proposed explanations include direct irritation of the airways by inhaled sulphur dioxide gas and immune-mediated reactions.
Adverse reactions to sulphites in sensitive individuals range from skin flushing, urticaria and abdominal pain to life-threatening anaphylaxis and bronchospasm; most studies report a prevalence of sulphite sensitivity of 3 to 10% among asthmatic subjects.
In a double-blind, placebo-controlled challenge of wine-sensitive asthmatics, sulphite additives in wine were confirmed to trigger measurable falls in lung function in a proportion of participants.
Sulphites are among the 14 major allergens recognised under UK and EU food law, requiring mandatory label declaration when present above 10mg per kg or per litre in the finished product.
In 2022, the European Food Safety Authority carried out a follow-up review of all sulphite additives (E220 to E228) and withdrew the previous temporary acceptable daily intake of 0.7mg of sulphur dioxide equivalents per kilogram of body weight per day. The authority concluded that the available toxicity data was no longer adequate to set a firm safe daily level. The trigger was animal evidence of delayed nerve-cell responses to stimuli, a sign of early nervous system disturbance. Using a margin-of-exposure approach, EFSA found that high consumers in most population groups, including children and adults, had margins below the benchmark considered acceptable, meaning their estimated exposures could exceed what the authority judged prudent.
The EFSA Panel withdrew the temporary group ADI because the toxicity database was inadequate to derive an ADI; new evidence from animal studies supported sulphite-induced neurotoxic effects including prolonged visual evoked potential latency.
Using a refined exposure scenario, margins of exposure fell below 80 for high consumers in all population groups except adolescents, raising a safety concern; children aged 3 to 10 potentially exceeded the prudent level by up to 12.5% and adults by up to 60%.
EFSA called for new toxicological data to address remaining gaps, particularly chronic and reproductive toxicity studies and better characterisation of human hypersensitivity reactions.
Sulphites are legally classified as one of the 14 major allergens under UK and EU food law. Any food or drink containing them above 10mg per kg or per litre must declare them prominently on the label, regardless of whether they were added directly or arrived via an ingredient. This threshold is very low compared with most other allergen thresholds, reflecting the real risk of reactions in sensitive consumers.
Sulphur dioxide and sulphites are listed as one of the 14 major allergens in Annex II of UK food information legislation; mandatory declaration is required when total sulphur dioxide exceeds 10mg per kg or per litre in the product as consumed.
People with asthma, particularly those who use steroid inhalers or have a history of reactions to wine or dried fruit. Also those with known sulphite sensitivity or multiple food allergies. Look for 'sulphites', 'sulphur dioxide', 'E228', 'E220', 'E221', 'E222', 'E223', 'E224', 'E226' or 'E227' in the allergen declaration or ingredient list. UK law requires bold or otherwise emphasised allergen text. Our allergen checker looks for the whole E220 to E228 group in a scanned pack's ingredient list rather than one number at a time. Check the label as well.
E228 is one of eight sulphite additives (E220 to E228) evaluated together by regulators because they all release sulphur dioxide in food. The allergen story is the most established: sulphites are formally recognised as a major allergen under UK law, with a mandatory-declare threshold lower than almost any other food allergen, because reactions in asthmatics are real and can be severe. The newer concern, from EFSA's 2022 review, is less certain: animal studies showed early signs of nervous system disturbance at higher doses, which led EFSA to withdraw the safe daily intake figure rather than lower it, acknowledging the data were simply not good enough to set a new number. For heavy consumers of wine, dried fruit and similar high-sulphite foods, EFSA calculated that exposures in some groups could exceed what the authority considered prudent. The science here is moving, not settled, and new toxicological data are still being sought.
No. E228 is approved for use in the UK as a preservative under the assimilated EU Regulation 1333/2008, with authorised status confirmed from 31 December 2020. It is permitted in wine, dried fruits, beer, juices and other food categories at levels set by that regulation.
In 2022 EFSA reviewed all eight sulphite additives and found that the existing toxicity data were no longer adequate to set a firm acceptable daily intake. Animal studies had pointed to early nervous-system effects, which required a more cautious reference point. Because industry had not submitted new studies to fill the data gaps, EFSA withdrew the previous figure and is now asking for fresh chronic and reproductive toxicity data before it can set a new one.
E228 is most commonly found in wine and cider, where it prevents oxidation. It also appears in dried fruits such as apricots and sultanas, dried potato products, beer, fruit juices, vinegar and some pickles and seafood products. UK food law requires the label to show 'sulphites' or 'sulphur dioxide' (in bold or otherwise highlighted) whenever the total sulphite level in the finished product exceeds 10mg per kg or per litre.
E228 is a mineral salt with no animal-derived ingredients. The additive itself is vegan. However, some wine producers use animal-derived fining agents alongside sulphites, so wine containing E228 may not be vegan for unrelated reasons.
Last reviewed: 20 June 2026
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