Sulphites as a Food Allergen: Labelling Requirements for Wine, Food and Drink
Sulphur dioxide and sulphites are major allergens requiring declaration at concentrations above 10mg/kg. Here is what food and drink businesses need to know about sulphite labelling.
Sulphur dioxide and sulphites are among the 14 major allergens in UK and EU food law. Unlike most allergens, they are a preservative category rather than a food ingredient category, and they appear in a very wide range of products including wine, dried fruit, processed meats, and many convenience foods.
The Declaration Threshold
Sulphites must be declared on food labels when present at concentrations above 10 mg/kg or 10 mg/litre (expressed as sulphur dioxide). At lower concentrations, declaration is not required. This threshold-based rule is unique among the 14 allergens.
Foods Commonly Containing Sulphites
- Wine and beer (sulphites are widely used as preservatives)
- Dried fruits (apricots, raisins, sultanas are typically very high in sulphites)
- Processed meats and fish products
- Fruit juices and soft drinks
- Vinegar and vinegar-containing products (pickles, sauces, condiments)
- Dried vegetables and pre-prepared salads
Why Sulphites Matter for Allergic and Sensitive Consumers
Sulphite sensitivity causes reactions ranging from respiratory symptoms to anaphylaxis in sensitive individuals. People with asthma are at particular risk. Though sulphite reactions are less common than reactions to proteins like peanut or milk, they can be severe.
Labelling "Contains Sulphites"
On packaged food, sulphites present above the threshold must be declared in the ingredient list (emphasised) or in a Contains statement. Wine labelled in the UK must carry "Contains Sulphites" where present above the threshold.
How Sulphites Enter the Food Supply
Sulphites enter the food supply through two distinct routes: intentional addition as a preservative or antioxidant, and incidental carryover from ingredients or processing aids. When added deliberately, they may appear in ingredient lists under several permitted names — sulphur dioxide, sodium sulphite, sodium bisulphite, sodium metabisulphite, potassium bisulphite, potassium metabisulphite — each with its own E number from E220 to E228. Food business operators need to be aware of all these forms when reviewing supplier specifications, because the name used in a technical data sheet may differ from the name appearing in finished product documentation.
Carryover is particularly relevant for compound ingredients such as sauces, marinades, and prepared meal components. If a supplier adds sulphites to a fruit purée used as an ingredient in your product, those sulphites carry over into the final product and contribute to the overall concentration. Even if your own manufacturing process introduces no sulphites directly, the cumulative level from multiple compound ingredients may push the finished product above the 10 mg/kg declaration threshold. This makes thorough supplier specification review essential for any food business using pre-processed ingredients.
The distinction between deliberate addition and carryover also has implications for how you communicate with suppliers. Asking simply whether sulphites are "added" will not reveal carryover from sub-ingredients. A more reliable approach is to request the measured or calculated total sulphite content of the finished ingredient, expressed as sulphur dioxide equivalents. Supplier questionnaires should explicitly ask about both intentional use and carryover from raw materials to give you the information you actually need for labelling decisions.
Emphasis Requirements in the Ingredient List
When sulphites are declared within the ingredient list, allergen regulations in both the UK and EU require that the allergen be emphasised relative to the rest of the ingredient list. In practice this means using bold text, italic text, underlining, or a different font — any typographic treatment that makes the allergen name visually distinct from surrounding text. The requirement applies to all forms of the sulphite name: whether you write "sulphur dioxide," "sodium metabisulphite," or any other permitted designation, that word or phrase must be emphasised. It is not sufficient to simply include the E number without the chemical name when the product is sold in a context requiring full ingredient declaration.
The emphasis requirement catches businesses out more often than might be expected, particularly when labels are designed by people without allergen compliance training. Graphic designers working from a standard ingredient list template may not know that sulphites need to stand out typographically, especially when the ingredient list is long and formatted in a small font size. It is worth building allergen emphasis into label design briefs as an explicit specification rather than leaving it to be added at the proofing stage, where it is easy to overlook.
On Shopify product pages, emphasis requirements translate into how you present ingredient information in product descriptions or dedicated allergen fields. Plain text fields do not always support bold or italic formatting consistently across themes, so it is worth testing how your allergen declarations render in the storefront as well as in the backend. Using a structured allergen management tool rather than free-text fields reduces the risk of formatting being lost during theme updates or product imports.
Sulphites in Wine: Specific UK Labelling Rules
Wine occupies a particular position in sulphite labelling because it is almost universally treated with sulphur dioxide at some point during production, and because wine labelling is governed by a separate regulatory framework from general food labelling. In the UK, wine sold in bottle must carry a "Contains Sulphites" statement on the label when sulphites are present above the 10 mg/kg or 10 mg/litre threshold. This applies to both UK-produced wine and imported wine sold in the UK market. The statement is typically required regardless of whether a full ingredient list is provided, which has historically been optional for wine.
From 8 December 2023, new rules introduced by UK Retained EU Law and aligned changes mean that wines produced and labelled after that date must include a full ingredient list and nutrition declaration, bringing wine labelling much closer to general food labelling requirements. For sulphites specifically, this means the allergen must now appear in an ingredient list with appropriate emphasis, in addition to or as part of the existing "Contains Sulphites" convention. Shopify merchants selling wine online need to ensure their product listings reflect both the on-label declaration on the physical bottle and any statutory information required for distance selling.
For merchants selling wine through a Shopify store, it is important to remember that distance selling rules require allergen information to be available to the customer before purchase is completed, not just on the physical label delivered with the product. This means your product page must clearly communicate the presence of sulphites at or above the threshold. Relying on the customer to read the bottle when it arrives is not compliant with UK food information regulations. Structured allergen fields on each product listing, kept current and auditable, are the practical solution.
Managing Sulphite Declarations Across a Product Range
For food businesses with more than a handful of products, managing sulphite declarations manually across a Shopify catalogue quickly becomes error-prone. Products are reformulated, suppliers change raw materials, and threshold status can shift without any obvious trigger. A product that previously sat below 10 mg/kg may exceed the threshold following a supplier change that you were not explicitly notified about. Without a systematic process for reviewing allergen status when specifications are updated, labelling errors can persist undetected until a customer complaint or regulatory inspection brings them to light.
A matrix approach to allergen management — where each product is mapped against each of the 14 allergens, with sulphite threshold status recorded explicitly — makes it far easier to audit your range and identify products that need review. When a supplier specification changes, you update the relevant entry in the matrix and immediately see which finished products are affected. This structured approach also makes it straightforward to generate allergen summaries for each product listing on your Shopify store, ensuring that what is displayed to the customer reflects your current formulation rather than an outdated version of the ingredient information.
Staff training is the other essential element. Anyone involved in product development, procurement, or labelling sign-off should understand the 10 mg/kg threshold rule, the multiple permitted names for sulphites, the emphasis requirement, and the distinction between deliberate addition and carryover. Without that knowledge, errors are almost inevitable in a busy production or buying environment. Written procedures supported by a centralised allergen management tool are the most reliable way to ensure consistent compliance as your team and product range grow.
Sulphites and "May Contain" Statements
Unlike the 14 major allergens for which precautionary allergen labelling ("may contain") is a common industry practice, sulphite cross-contamination is rarely the subject of "may contain" statements in the same way. This is partly because sulphites are a chemical preservative rather than a particulate allergen, and cross-contamination in the sense of physical transfer between production lines is less relevant than it is for, say, peanut or tree nut. However, there are scenarios where residual sulphites from cleaning agents or shared processing equipment used with high-sulphite products could contribute to contamination, and these should be assessed as part of your HACCP-based allergen risk management.
Where a risk assessment identifies a genuine risk of sulphite contamination above the declaration threshold, you should document that assessment and consider whether a precautionary statement is warranted. Voluntary precautionary labelling for sulphites is less standardised than for other allergens, so if you do use it, ensure the wording is accurate and specific rather than a generic blanket disclaimer. Overly broad precautionary statements that cover allergens not genuinely at risk can erode consumer trust and may draw regulatory scrutiny.
For Shopify merchants managing a range that includes both high-sulphite and low-sulphite products, Allergen Matrix at saltai.app allows you to record and display allergen status — including threshold-based sulphite declarations — consistently across your entire catalogue, reducing the risk of errors and giving customers the clear information they need.
Try Allergen Matrix free at saltai.app — no credit card required.
SaltAI Team
SaltAI builds focused Shopify apps for food merchants and general merchants. Every app is tested in production at a real food store — including Vanda's Kitchen — before it ships.