Food allergies are a serious health concern affecting millions of people across the UK and beyond. For those who suffer from them, even trace amounts of an allergen can cause a reaction — ranging from mild discomfort to life-threatening anaphylaxis. That’s why it’s vital for individuals, food handlers, and businesses to understand which foods are most likely to cause allergic reactions, and more importantly, where these ingredients might be hiding.
The UK’s Food Information Regulations identify 14 specific allergens that must be clearly declared when used as ingredients. These allergens can appear in a wide range of products, often where you’d least expect them.
Whether you’re a consumer trying to stay safe or a business aiming to ensure compliance, knowing the top allergens and how they’re commonly disguised is crucial for allergy awareness. Let’s break down each one.
1. Celery
Celery allergies can be severe, and both the stalks and seeds can cause reactions. It’s found not only in fresh produce but also in spice blends, stock cubes, soups, and processed meats. Celery salt is another common culprit, often used in seasonings and salad dressings.
This allergen can be hidden in pre-packaged products or ready meals, making it essential to always read the ingredients list thoroughly. Restaurants may also use celery in bases like mirepoix or as part of marinades and sauces.
2. Cereals Containing Gluten
Gluten is a protein found in wheat, rye, barley, and oats. It’s a well-known trigger for coeliac disease and gluten allergies. These cereals appear in bread, pasta, cakes, and biscuits, but also in less obvious items like soy sauce, beer, gravies, and some sweets.
Many processed foods contain gluten, either as a thickener or filler. Cross-contact is a concern, especially in shared kitchens or bakeries, so vigilance is key for those with gluten sensitivities.
3. Crustaceans
Crustaceans include crabs, prawns, and lobsters. Reactions to these shellfish can be severe, and the allergen can linger on cooking equipment or surfaces. Crustaceans are common in Asian cuisine, seafood sauces, and even some fish stocks.
Always check labels on mixed seafood products, sushi, and prawn crackers. Even trace amounts from a shared fryer can be dangerous for allergic individuals.
4. Eggs
Eggs are widely used in both sweet and savoury dishes — from cakes and mayonnaise to pasta and quiches. They can be hard to detect, particularly in baked goods and processed foods.
Egg proteins may also appear in less obvious places like wine (used for fining), marshmallows, or some vaccines. For people with egg allergies, it’s vital to confirm ingredients every time.
5. Fish
Fish allergies can be triggered by even tiny amounts of protein, and fish is often used in unexpected places. Common hiding spots include salad dressings (like Caesar), Worcestershire sauce, and bouillons.
Surimi (imitation crab), anchovy paste, and fish oils used in supplements or fortified foods can also cause reactions. Always verify ingredients, especially in ready meals or sauces.
6. Lupin
Lupin is a legume that’s related to peanuts and is increasingly used in gluten-free and high-protein baked goods. It can be found in flour, pastries, and bread, especially in European imports.
Its similarity to peanuts means people allergic to one may react to the other. Because lupin is still relatively unknown, many don’t expect to encounter it — making education and labelling all the more important.
7. Milk
Milk allergies are different from lactose intolerance and involve an immune response to milk proteins. Dairy is present in countless foods: chocolate, baked goods, sauces, soups, and processed meats.
Milk derivatives like whey and casein can be hidden in protein powders, non-dairy creamers, or flavourings. Vegan or plant-based doesn’t always mean milk-free, so it’s essential to check thoroughly.
8. Molluscs
Molluscs include mussels, clams, oysters, and squid. These are common in seafood dishes, but mollusc extracts can also be found in sauces, fish stews, and even in some supplements or cosmetics.
As with crustaceans, cross-contact in kitchens is a serious concern. Even airborne particles during cooking can trigger reactions in highly sensitive individuals.
9. Mustard
Mustard is a common allergen in the UK and can appear in sauces, dressings, marinades, processed meats, and spice blends. It comes in many forms — powder, seeds, oil, and paste — all of which can trigger allergies.
Look out for mustard as an ingredient in prepared salads (like coleslaw or potato salad), chutneys, and curries. In some products, it might simply be listed under “spices.”
10. Nuts (Tree Nuts)
Tree nuts include almonds, cashews, walnuts, hazelnuts, pecans, and more. These are commonly found in desserts, cereals, sauces, nut oils, and snacks.
Tree nut traces can also be present in products made in shared facilities, so people with allergies should be cautious with foods labelled “may contain.” Nut flours and extracts, like almond flour or hazelnut flavouring, are other hidden sources.
11. Peanuts
Peanut allergies are among the most well-known and potentially life-threatening. Peanuts are found in spreads, confectionery, sauces (like satay), and baked goods.
Watch for peanut-derived ingredients like peanut oil (especially if unrefined), peanut flour, or groundnuts. They may also be present in less obvious foods like curries or protein bars.
12. Sesame Seeds
Sesame is common in baked goods like burger buns, crackers, and breadsticks. It’s also used in Middle Eastern and Asian dishes — especially as tahini, an ingredient in hummus.
Sesame oil, pastes, and hidden seeds in processed products can all cause reactions. Some breads contain ground sesame flour, making it even harder to detect visually.
13. Soya
Soya is widely used in processed foods — not just in tofu or soy sauce, but also in baked goods, meat substitutes, soups, chocolate, and even infant formula. It’s a highly versatile ingredient and can be hard to avoid.
Soya lecithin, a common emulsifier, is used in chocolates, dressings, and packaged foods. People with soya allergies need to be especially cautious with “plant-based” products.
14. Sulphur Dioxide (Sulphites)
Sulphites are used as preservatives in dried fruits, wine, beer, vinegar, and processed meats like sausages. They can cause respiratory reactions and other symptoms, especially in people with asthma.
Foods like pre-cut potatoes, frozen shellfish, or fruit juices may also contain sulphites to preserve colour and freshness. Even in small amounts, they must be declared on the label if above a certain level.
Don’t Just Read Labels — Learn the Risks Behind Them
The presence of these 14 allergens isn’t always obvious, and they can be hidden in flavourings, additives, or processing methods. It’s not enough to simply scan a label — consumers and food handlers alike need to learn about allergens and understand how they are used across different cuisines and products.
Whether you’re managing your own allergy or supporting someone else, having the right knowledge and vigilance is key. By improving allergy awareness, reading ingredient lists carefully, asking the right questions, and maintaining strict food handling procedures, we can create safer dining environments for everyone. The more you know, the better protected you’ll be — and the more empowered you’ll feel in any food setting.
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