UK vs US allergens: the quick comparison
United Kingdom: 14 regulated categories
Celery, cereals containing gluten, crustaceans, eggs, fish, lupin, milk, molluscs, mustard, nuts, peanuts, sesame, soybeans, and sulphur dioxide and sulphites. Emphasised in the ingredients list.
United States: nine major allergens
Milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans and sesame (the "Big Nine"). Named in the ingredients or in a "Contains" statement.
| Feature | United Kingdom | United States |
|---|---|---|
| Number of regulated major allergen categories | 14 | 9 |
| Wheat | Included within cereals containing gluten | Major allergen |
| Barley and rye | Included within cereals containing gluten | Not separate major allergens |
| Crustaceans | Regulated | Major allergen |
| Molluscs | Separate regulated category | Not one of the nine |
| Celery | Regulated | Not one of the nine |
| Mustard | Regulated | Not one of the nine |
| Lupin | Regulated | Not one of the nine |
| Sesame | Regulated | Major allergen since 2023 |
| Sulphites | Regulated above the applicable threshold | Separate declaration rules, not one of the nine |
| Ingredient-list allergen emphasis | Generally required for applicable prepacked foods | Major allergen source identified in the ingredient list or a Contains statement |
| Precautionary 'may contain' statements | Generally voluntary | Generally voluntary |
These are broad comparisons. Particular foods, processing methods, exemptions and regulatory authorities can affect the exact requirements.
What are the UK's 14 regulated food allergens?
The UK identifies the following categories:
- Celery
- Cereals containing gluten
- Crustaceans
- Eggs
- Fish
- Lupin
- Milk
- Molluscs
- Mustard
- Nuts
- Peanuts
- Sesame
- Soybeans
- Sulphur dioxide and sulphites above the specified threshold
For applicable foods, these allergens must be declared when used as ingredients, subject to the relevant rules and exemptions.
The UK system is closely aligned with the European Union's 14-category framework.
Read our complete guide to the UK's 14 food allergens.
What are the nine major food allergens in the US?
The United States identifies:
- Milk
- Eggs
- Fish
- Crustacean shellfish
- Tree nuts
- Peanuts
- Wheat
- Soybeans
- Sesame
These are often called the Big Nine.
The original US federal framework identified eight major food allergens.
Sesame became the ninth on 1 January 2023 under the FASTER Act.
The rules require covered foods to identify the source of major food allergens used as ingredients, including applicable protein-derived ingredients.
The most important differences explained
1. The UK regulates cereals containing gluten; the US identifies wheat
This is one of the most important distinctions for people managing coeliac disease or gluten-related dietary requirements.
The UK's regulated category includes:
- Wheat
- Barley
- Rye
- Oats
- Spelt
- Khorasan wheat
- Related hybridised strains
The US major-allergen framework identifies wheat.
Barley and rye are not separate members of the US nine-major-allergen list.
Why does this matter?
Imagine an American product containing barley malt.
Barley may be listed in the ingredients, but the product would not necessarily need a major-allergen declaration for barley under the US Big Nine framework.
Someone with coeliac disease still needs to consider barley-derived gluten.
A US label without a wheat allergen declaration is not automatically gluten-free.
Is gluten-free the same as wheat-free?
No.
Gluten-free and wheat-free address different requirements.
Some specially processed wheat-derived ingredients can meet gluten-free standards.
However, their suitability for someone with wheat allergy is a separate question.
Read our wheat and gluten ingredient guide.
2. The UK regulates molluscs; the US Big Nine does not
The UK separates seafood into three relevant allergen categories:
- Fish
- Crustaceans
- Molluscs
The US major-allergen list includes fish and crustacean shellfish.
It does not include molluscs as a major-allergen category.
What counts as a mollusc?
Examples include:
- Oysters
- Mussels
- Clams
- Scallops
- Squid
- Octopus
- Snails
Why does this matter?
A US product containing oyster extract may identify oysters in the ordinary ingredients list without using the same major-allergen declaration required for crustacean shellfish.
A person with mollusc allergy must therefore check the complete ingredient information.
Are prawns and shrimp treated differently?
Both are crustaceans.
They fall within the relevant regulated category in both countries.
Is fish allergy the same as shellfish allergy?
No.
Fish, crustaceans and molluscs are different groups.
An allergy to one does not automatically establish a diagnosed allergy to all the others.
Read our shellfish ingredient guide.
3. Celery is regulated in the UK but not one of the US nine
Celery can appear in:
- Soups
- Stocks
- Bouillon
- Seasoning mixes
- Sauces
- Salads
- Prepared meals
Celeriac is also part of the celery allergen category.
In the UK, applicable food labels must identify celery when used as an ingredient.
In the US, celery is not one of the nine major food allergens.
It may still appear in ingredient information, but shoppers should not expect a Big Nine allergen declaration for celery.
4. Mustard is regulated in the UK but not one of the US nine
Mustard is commonly found in:
- Dressings
- Sauces
- Marinades
- Pickles
- Spice blends
- Prepared meals
The UK regulates mustard as an allergen category.
The US Big Nine framework does not.
This means a shopper with mustard allergy needs to examine US ingredient lists carefully, including composite ingredients and seasonings.
5. Lupin is regulated in the UK but not one of the US nine
Lupin is a legume that may be used in:
- Bakery products
- Flour mixtures
- Gluten-free foods
- Plant-based products
- Protein-rich foods
Lupin is one of the UK's regulated allergens.
It is not one of the US Big Nine.
Is lupin related to peanuts?
Lupin and peanuts are both legumes.
Some people with peanut allergy can also react to lupin, but this is not universal.
An individual allergy assessment is important.
6. Sulphites are treated differently
The UK includes sulphur dioxide and sulphites among its 14 regulated allergen categories when the relevant concentration exceeds 10 mg/kg or 10 mg/litre, expressed as total SO₂.
Sulphites can be found in certain:
- Wines
- Dried fruits
- Preserved foods
- Drinks
- Condiments
- Processed potato products
The United States also has specific sulphite declaration requirements in certain circumstances.
However, sulphites are not one of the US nine major food allergens.
Does this mean sulphites are unregulated in America?
No.
Not being included in the Big Nine does not mean a substance is entirely unregulated.
The US has separate rules addressing sulphites, including declaration requirements at specified levels in relevant circumstances.
The important distinction is between major-allergen status and other food labelling requirements.
7. Sesame is now regulated in both countries
Sesame is included in the UK's 14 categories.
It became the ninth major food allergen in the US in January 2023.
Sesame may appear under names including:
- Sesame seeds
- Tahini
- Tahina
- Benne
- Gingelly oil
- Sesame paste
Why was sesame added in the US?
The FASTER Act expanded federal major-allergen recognition to include sesame.
This introduced specific sesame allergen declaration requirements for covered products.
Does halva always contain sesame?
No.
Many varieties contain sesame, but halva recipes vary.
Check the specific product.
Read our sesame ingredient guide.
How do British food labels show allergens?
In the UK, applicable prepacked food labels generally identify regulated allergens within the ingredients list using emphasis.
Bold type is common, although other permitted methods may be used.
Example UK ingredients list
Chocolate biscuits (UK label)
Ingredients: Wheat flour, sugar, vegetable oil, milk powder, cocoa powder, soy lecithin.
Here, wheat, milk and soy are emphasised.
The exact declaration depends on the product and applicable requirements.
Are all allergens listed separately?
Not necessarily.
The allergen is generally identified within the ingredients list rather than through a separate US-style Contains statement.
For foods sold without conventional prepacked labelling, different methods of providing allergen information may apply.
How do American food labels show allergens?
For covered US foods, major allergen sources must be identified according to federal requirements.
This can be done through the ingredient list or a separate Contains statement.
Example US label using a Contains statement
Chocolate biscuits (US label)
Ingredients: Wheat flour, sugar, vegetable oil, milk powder, cocoa powder, soy lecithin.
Contains: Wheat, Milk, Soy.
Example US label using ingredient identification
US label, allergens named in the ingredients
Ingredients: Flour (wheat), whey (milk), lecithin (soy).
A separate Contains statement is not always required if the applicable allergen identification requirements are met in the ingredients list.
Are allergens always printed in bold in America?
No.
The US rules do not simply mirror the UK's general ingredient-list emphasis approach.
This is why shoppers should understand the labelling system used in the country where the product is sold.
Are US food labels less safe than UK labels?
It would be misleading to make that general claim.
The systems use different regulated categories and declaration methods.
The UK's 14 categories provide broader coverage of certain allergen groups.
The US framework identifies nine major allergens and has other food safety and labelling requirements beyond that list.
Neither system covers every possible allergy.
Neither guarantees that food cannot contain an undeclared allergen through an error or cross-contact.
The practical lesson is to understand the relevant rules and check the actual ingredients.
Are there differences in tree nut definitions?
Yes.
Tree nut definitions and the specific nuts covered by regulatory allergen categories can differ.
The UK's regulated nut category identifies eight specified nut types:
- Almonds
- Hazelnuts
- Walnuts
- Cashews
- Pecans
- Brazil nuts
- Pistachios
- Macadamia nuts
The US framework uses its own regulatory interpretation of tree nuts, which has been subject to FDA guidance updates.
Do not assume that every botanical nut, culinary nut or seed is classified identically in both countries.
For example, peanuts are legumes, not tree nuts.
Coconut and pine nuts require separate consideration rather than automatic classification as members of the UK's specified eight-nut category.
Since January 2025 the FDA's tree nut list has 12 entries, including pine nuts but no longer coconut, chestnut or shea, so older lists online may not match current US guidance.
A person with an allergy outside a regulated category still needs to check the ingredient.
Read our tree nut ingredient guide.
Do UK and US allergen rules cover every food?
No.
Different product categories and selling circumstances can be governed by different requirements.
In the UK
The way allergen information is provided depends partly on whether the food is:
- Prepacked
- Prepacked for direct sale
- Sold loose
- Prepared in a restaurant or café
In the US
The FDA regulates many packaged foods.
Other federal agencies regulate certain categories, including most meat, poultry and some egg products.
Restaurants and other foodservice settings are also subject to relevant state and local requirements.
The Big Nine packaged-food labelling rules should not be assumed to apply identically to every meal or product.
What about 'may contain' warnings?
Both countries allow voluntary precautionary allergen information.
Examples include:
- May contain peanuts
- May contain milk
- Made on equipment that also processes nuts
- Made in a facility that handles sesame
These statements generally address possible unintended allergen presence through cross-contact.
They are different from deliberate ingredient declarations.
Is 'may contain' compulsory?
Precautionary allergen statements are generally voluntary in both countries.
Does no warning mean no risk?
No.
The absence of a precautionary statement does not guarantee that cross-contact is impossible.
Can warning phrases be ranked by risk?
Not reliably.
Terms such as 'traces', 'shared equipment' and 'shared factory' do not provide a universal numerical risk scale.
Read our complete guide to 'may contain' warnings.
What about highly refined oils and allergen exemptions?
Some ingredients derived from regulated allergen sources are subject to specific exemptions.
One example is highly refined oils.
Peanut oil
Highly refined peanut oil may contain very little residual peanut protein.
Unrefined or cold-pressed peanut oils can differ.
The US major-allergen framework includes a specific exemption for highly refined oils derived from major allergens.
The UK has its own ingredient-specific exemptions, which should not be assumed to be identical. For example, UK rules exempt fully refined soybean oil, but they give no exemption for refined peanut oil.
Does an exemption mean an ingredient is medically safe?
No.
A legal labelling exemption is not a personalised clinical assessment.
People with diagnosed allergies should follow individual medical advice.
What about fish gelatine and wheat-derived glucose syrup?
Certain fish-derived and cereal-derived ingredients have specific exemptions under UK food allergen information rules.
Their legal treatment depends on the ingredient and processing.
These exemptions should not be generalised to every fish gelatine or wheat-derived ingredient.
Buying American food in the UK
Imported foods sold in the UK must comply with the applicable UK food information requirements.
A product may have a UK-specific label or an additional sticker providing the required information.
What should you check?
- Read the full ingredient information supplied for the product.
- Look for the allergens relevant to your requirements.
- Check any additional UK labelling.
- Review precautionary statements.
- Don't assume the US Big Nine covers all 14 UK categories.
- Ask the seller or manufacturer if the information is incomplete or contradictory.
A product being imported does not automatically mean its original overseas label is sufficient for UK sale.
Buying British food in the US
A British product sold in the US may carry additional or adapted information to meet relevant US requirements.
The original British packaging may also use terminology unfamiliar to American shoppers.
Examples include:
| British term | Common US equivalent |
|---|---|
| Soya | Soy |
| Prawns | Shrimp in many food contexts |
| Maize | Corn |
| Cornflour | Cornstarch |
| Icing sugar | Powdered sugar |
| Aubergine | Eggplant |
| Courgette | Zucchini |
These are language examples rather than a list of regulated allergen synonyms.
For allergy checking, the exact ingredient and its source matter more than the regional spelling.
What should travellers with food allergies know?
If you're travelling between the UK and US, the following steps can help you interpret food information.
Know your specific allergens
Don't rely only on the national regulated list.
Learn the local labelling system
Understand how allergen declarations normally appear.
Check the complete ingredients list
Don't look only for a bold word or a Contains statement.
Be aware of category differences
Barley, rye, molluscs, celery, mustard and lupin are particularly relevant examples.
Ask questions when eating out
Restaurant allergen information and preparation practices may differ.
Carry your individual allergy-management information
Follow medical advice about emergency medication and your action plan.
Check imported products carefully
A translated or supplementary label may provide important information.
Read our guide to ingredient labels abroad.
Why ClearaScan starts with the UK's 14 allergen categories
ClearaScan uses the UK's 14 regulated allergen categories as a broader starting framework for suggested Ingredient Guard rules.
This helps users consider categories such as:
- Celery
- Mustard
- Lupin
- Molluscs
- Cereals containing gluten
These are not all separately included in the US Big Nine framework.
However, using 14 categories does not guarantee greater safety, greater accuracy or complete allergen detection.
People can have allergies outside both regulatory lists.
Individual dietary needs can differ.
Ingredient recognition and interpretation also have limitations.
ClearaScan therefore supports personalised Ingredient Guard rules rather than treating a national allergen list as a complete description of everyone's requirements.
Checking the actual label
ClearaScan reads photographs of ingredient labels on the products you're holding.
It checks recognised text against the rules you've selected.
This can be particularly useful when comparing products with unfamiliar terminology or different labelling conventions.
However, the app cannot independently establish compliance with UK or US food law, determine whether an undeclared allergen is present or guarantee clinical suitability.
Always verify the original packaging.
