List of the 14 most common food allergens

Last Updated : 09 June 2025

Key takeaways

• Food allergens are substances in food that trigger an immune system response in some individuals, leading to allergic reactions. These allergens are almost always proteins naturally found in food.
• Symptoms of a food allergy can range from mild to life-threatening and complete avoidance of the allergen is the only way to prevent allergic reactions.
• The EU mandates labelling of 14 common allergens to help consumers make informed choices. These include cereals containing gluten (wheat, rye, barley, oats), crustaceans, eggs, fish, peanuts, soybeans, milk, nuts, celery, mustard, sesame seeds, sulphur dioxide and sulphites, lupin, and molluscs.
• If you have a food allergy, always read ingredient labels and ask about ingredients when dining out. If you suspect a food allergy, consult your GP.

Food allergens are substances in food that can trigger an allergic reaction in some individuals. These allergens are almost always proteins naturally found in food. Proteins are responsible for allergic reactions because they can resist digestion and trigger the immune system. When a person with a food allergy eats even a small amount of the allergenic protein, their immune system mistakenly identifies it as harmful and releases chemicals like histamine, causing allergy symptoms. These reactions can range from mild symptoms, like itching or hives, to severe and life-threatening conditions, such as anaphylaxis. The only way to manage a food allergy is to avoid the food that makes the person ill.¹

Manufacturers of food sold in the EU must label 14 most common allergens under EU law. The legislation also requires that allergen information must be present for foods that are not prepacked.² This article lists the most common food allergens, along with examples of foods to watch out for that contain them.

Fig. 1 – 14 most common food allergens in Europe.

Cereals containing gluten

An allergy to certain cereals can be caused both by inhalation of cereal flour (baker’s asthma) and by eating cereal-based products (food allergy). Most commonly, the gluten protein complex (a combination of gliadin and glutenin protein) that is found in the cereal seed is responsible for causing an allergic reaction in sensitive individuals, but also non-gluten components, such as albumin and globulin proteins, a-amylase inhibitor and lipid transfer proteins, can cause an allergic reaction.

Gluten is found in several cereals (grains), such as wheat (including spelt and Khorasan wheat), rye, barley, oats, or their hybridised strains (i.e., types of grains that have been specifically bred by combining different varieties to create new ones with improved characteristics) such as triticale. The name of these cereals will be highlighted in the ingredients list of products that contain them.

It’s estimated that the prevalence of wheat allergy is as low as 0.4% in young children, and this frequently resolves during adolescence.¹

A gluten allergy is different from coeliac disease, wheat intolerance, and gluten sensitivity. Unlike a gluten allergy, coeliac disease is an autoimmune disorder that causes damage to the lining of the small intestine which decreases the ability of the gut to absorb nutrients and can lead to nutritional deficiencies. Gluten sensitivity is a condition where individuals experience symptoms similar to coeliac disease after eating gluten, but without the autoimmune response or intestinal damage. Someone with a wheat intolerance may experience symptoms such as bloating, wind, gurgling and abdominal pain after eating wheat which can be due to the high level of fructans (a type of fermentable carbohydrate) and difficulties to digest these. This reaction doesn’t involve the immune system, unlike someone who has an allergy to cereal containing gluten. The symptoms of a gluten allergy can include hives, swelling, nausea, vomiting, breathing difficulties, and anaphylaxis.

Foods labelled as ‘gluten-free’ (containing ≤20 mg gluten/kg) are designed to be safe for people with coeliac disease, but they may still contain other proteins from cereals like wheat, rye, barley, or oats, which can trigger allergic reactions. People with a food allergy to any of the cereals containing gluten should not assume that gluten-free foods are safe.

While wheat-based glucose syrups (including dextrose), wheat-based maltodextrins, glucose syrups based on barley, and cereals used for making alcoholic distillates (including ethyl alcohol of agricultural origin) are made from cereals containing gluten, they’re excluded from having the mandatory allergen warning labelling requirements. This is because they’re not likely to cause adverse reactions in sensitive people.¹

Foods to watch for with a gluten allergy:³

• Breads (e.g., wheat breads, pittas, chapattis, croissants, crumpets, muffins, naans, tortillas, breadsticks, bagels, wraps, breadcrumbs, etc.)
• Wheat-based breakfast cereals and cereal bars
• Non-certified gluten-free oat cereals, porridges, and granolas
• Oat drink, oat-based alternative to yoghurt, and other dairy alternatives made from oats
• Pasta, pizza, and noodles (e.g., fresh or dried pasta, minestrone, tinned spaghetti)
• Grains, flours, and flakes (e.g., bulgur wheat, couscous, durum wheat, freekeh, einkorn, emmer, Kamut, malted wheat, semolina, farina, spelt, triticale, whole wheat, wheat bran, wheat germ)
• Breaded or battered fish/meats, sausages, and burgers and Scotch egg
• Cakes and desserts (e.g., pastries, cheesecake, sponges, pancakes, muffins, scones, doughnuts, ice cream cones, fruit crumble)
• Vegetables and fruits coated in breadcrumbs or batter
• Foods, such as chips, that have been fried in the same oil as breaded fish or chicken products
• Soups using wheat as thickening agents
• Condiments and sauces (e.g., gravy, soy sauce, stock cubes, ready meal/casserole mixes, mustard, stuffing, some spice mixes)
• Beer, ale, stout, lager, and malted milk drinks

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

The following cereals are typically safe for people with a cereal allergy: rice, maize, millet, sorghum, buckwheat, quinoa, amaranth, and teff. Be sure to check the label for any cross-contamination warnings.

Crustaceans

Crustaceans are a type of shellfish. They’re invertebrates (they have no backbone) with a segmented body and jointed legs. Crustaceans include crab, crayfish, langoustine, lobster (langoustine), prawn, shrimp, and scampi.³

People with a crustacean allergy react to the proteins of these foods. Crustacean allergies are different from fish allergies because the reactions commonly involve reacting to a different protein. Tropomyosin is the primary allergenic protein in crustaceans (and molluscs, another type of shellfish), while parvalbumin is the main allergenic protein in fish. However, tropomyosin is also the main allergenic protein in tilapia fish specifically.¹

If you’re allergic to one type of crustaceans, it’s safer to avoid all types because the allergenic protein is found in many types of crustaceans. Having a crustacean allergy also increases the risk of an allergy to molluscs, since they’re also shellfish. It’s best to consult your GP or allergy specialist in these cases.¹ People who are highly sensitive may also need to avoid inhaling cooking vapours of these shellfish (most commonly prawn), for example in the home, near a food processing factory or catering outlet.³

Foods to watch for with a crustacean allergy:³

• Crab, crayfish, langoustine, lobster, prawn, shrimp, and scampi
• Asian dishes (e.g., prawn fried rice, dim sum, sushi)
• Prawn crackers
• Sauces and broths made with shellfish stock
• Rice dishes such as paella, fried rice, and sushi rolls
• Stews, soups or casseroles such as seafood chowder or bouillabaisse
• Fish sauce and dishes that may include them, such as casseroles and stir-fries
• Dips or pâtés containing shellfish such as crab pâté, prawn cocktail dips, and seafood paste and spreads
• Fried foods cooked in shared oil with shellfish (e.g., fish and chips from a takeaway shop)
• Glucosamine supplements
• Some beer and wine which have been processed with shellfish
• Krill oil

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Eggs

Egg allergy is an adverse immune system response to the proteins found in egg (ovomucoid, ovalbumin, and lysozyme). Both egg whites and egg yolks contain allergenic proteins, making them unsuitable for those with an allergy. Egg products are used widely by the food industry, including in dairy products, confectionary, beverages, ready prepared meals, cakes, icings, custard fillings, and frozen bakery products, so it’s important to check food labels and ask about ingredients when dining out.¹

When eggs are cooked, its proteins change in structure. This causes them to bind less effectively to our immune system cells and decreases their potential to cause an allergic reaction. Some people with an egg allergy can eat well-cooked eggs, such as those found in baked goods like cakes, but may experience allergic reactions when eating lightly cooked (e.g., scrambled eggs) or raw eggs (e.g., fresh mayonnaise or chocolate mousse).¹ Your GP or allergy specialist can help determine whether you should avoid all egg-containing foods.

It’s estimated that egg allergy is prevalent in about 1.5-2.5% of young children (<3 years) and 0.1-1% of older children and adults.¹

To minimise allergy risk, guidelines recommend introducing well-cooked, but not raw egg or uncooked pasteurised, egg during complementary feeding.⁴ Introduce around 2 g egg protein (approximately 1/3 of an egg) per week to your infants’ diet, starting from 4 to 6 months of life. It’s always best to consult your GP or allergy specialist before introducing egg to infant’s diets.

Foods to watch for with an egg allergy:³

Baked, well-cooked egg:

• Cakes and desserts (e.g., Jaffa cakes, sponge fingers, plain cakes, waffles, manufactured Yorkshire puddings, meringue)
• Dried or fresh egg pasta and dried egg noodles
• Prepared meat dishes and sausages containing egg
• Egg glaze on pastry (e.g., sausage rolls)
• Mycoprotein
• Gravy granules containing egg

Lightly cooked egg:

• Scrambled, boiled, fried, or poached egg
• Cakes and desserts (e.g., homemade meringues, flan, egg custard, crème brûlée, crème caramel, lemon curd, pancakes, sticky Yorkshire pudding, bread and butter pudding)
• Quiche, Spanish tortilla, egg fried rice
• Egg in homemade batter (e.g., tempura batter, chicken dipped in egg and breadcrumbs mix)
• Condiments and sauces (e.g., Hollandaise sauce)
• Dried or fresh egg pasta and dried egg noodles (cooked for less than 10 minutes)

Undercooked egg:

• Cakes and desserts (e.g., raw batter, royal icing, fresh/homemade mousse)
• Condiments and sauces (e.g., mayonnaise, horseradish sauce, salad cream)
• Ice creams and sorbets
• Cheeses if they contain egg white lysozyme or other egg proteins
• Chocolate bars containing egg in their filling and some soft-centred chocolates
• Some prawn crackers
• Spaghetti alla carbonara
• Products that contain the food additives egg lysozyme (E1105) and egg lecithin (E322)

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen. Plant-based products are often safe for people with egg allergies, but labels should always be checked for risk of cross-contamination.

Fish

Fish are vertebrates (they have a backbone). Most fish are covered in scales and have fins. Fish includes anchovy, basa, cod, cuttlefish, eel, flounder, grouper, haddock, hake, halibut, mackerel, monkfish, perch, pike, pilchards, plaice, pollock, salmon, sardine, sea bass, sea bream, snapper, swordfish, trout, tuna, turbot, whitebait, whiting, and tilapia.³

People with a fish allergy react to the proteins of these foods. It's estimated that fish allergy is well below 1% in the general population. Fish allergy is rarely outgrown in adulthood. Fish is one of the foods most common for causing severe anaphylaxis.¹People who are highly sensitive may also need to avoid inhaling cooking vapours of these fish, for example in the home, near a food processing factory or catering outlet.³

Fish allergies are different from shellfish allergies (crustaceans and molluscs) because the reactions commonly involve reacting to a different protein. Parvalbumin is the primary allergenic protein in fish, while tropomyosin is the main allergenic protein in both crustaceans and molluscs (although tropomyosin can also be found in tilapia fish).¹

If you’re allergic to one type of fish, it’s safer to avoid all types because the allergenic protein is found in many types of fish. Sometimes people with a fish allergy can eat shellfish safely. It’s best to consult your GP or allergy specialist in these cases.¹

Fish gelatine used as carrier for vitamin or carotenoid preparations, or fish gelatine or isinglass used as fining agent in beer and wine are exempt from having the mandatory allergen warning labelling requirements. Although typical doses of fish gelatine are tolerated by most people allergic to fish, anaphylaxis from fish gelatine has been described as some people may be sensitive to extremely low quantities of the allergen.⁵ It’s best to consult your GP or allergy specialist with regards to fish gelatine.

Foods to watch for with a fish allergy:^1,3

• Surimi
• Asian dishes (e.g., prawn fried rice, dim sum, sushi)
• Sauces and broths made with shellfish stock (e.g., Worcestershire sauce)
• Rice dishes such as paella, fried rice, and sushi rolls
• Stews, soups or casseroles such as seafood chowder or bouillabaisse
• Fish sauce and dishes that may include them, such as casseroles and stir-frys
• Dips or pâtés containing fish such as taramasalata, salmon, and caviar or roe (fish eggs)
• Fried foods cooked in shared oil with fish (e.g., fish and chips from a takeaway shop)
• Caeser salads, pizzas, and sauces containing Anchovy
• Beer and wine which has been processed with fish isinglass
• Chondroitin supplements
• Fish collagen
• Fish oils

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Peanuts

Peanut allergy is an adverse immune system response to peanut proteins. While commonly thought of as a nut because of their similar nutritional composition, peanuts are botanically part of the legume family, which also includes pea, bean, soybean, lupin, lentil, and fenugreek.¹

Peanut allergy is one of the most common causes of allergic reactions and can be severe or even fatal. The most severe reactions have been seen in people with asthma. It’s estimated that between 0.1 to 1.8% of Europeans are allergic.¹

Since peanuts are from a different plant family than tree nuts, someone with a peanut allergy isn’t automatically also allergic to tree nuts (almonds, hazelnuts, walnuts, cashews, pecan nuts, Brazil nuts, pistachio nuts, shea nuts, and/or macadamia (Queensland) nuts. However, having a peanut allergy does increase the risk of developing a tree nut allergy. Approximately 20 to 50% of people with a peanut allergy are also allergic to tree nuts. Having a peanut allergy also raises the risk of developing allergies to sesame and lupin.¹ It’s important to consult a GP or allergy specialist to determine whether sesame, lupin, or tree nuts can be safely included in the diet.

To minimise allergy risk, guidelines recommend introducing peanuts during complementary feeding.4,6 If your infant has severe eczema, egg allergy, or both (conditions that increase the risk of peanut allergy), introduce peanuts as early as 4 to 6 months of age. If your infant has mild to moderate eczema, introduce peanuts around 6 months of age.⁶ Give peanuts crushed, ground, or try a smooth nut butter to reduce the risk of choking. The amount of peanut protein to be eaten per week should be approximately 6 to 7 grams over 3 or more feedings. One feeding (2 g of peanut protein) looks like, for example, 9-10 g or 2 teaspoons of peanut butter or 8 g or 10 whole peanuts (2 ½ teaspoons of grounded peanuts). It’s always best to consult your GP or allergy specialist before introducing peanuts to infant’s diets.

Peanuts are also processed to make peanut (or groundnut) oil. People with a peanut allergy are generally advised to avoid crude (unrefined) peanut oil because it may contain peanut proteins that can trigger allergic reactions. However, highly refined peanut oil undergoes processing that removes most allergens, making it much less likely to cause a reaction. While the risk from refined peanut oil is low, extremely sensitive individuals could still react, so caution is recommended.¹

Foods to watch for with a peanut allergy:³

• Peanut butter and (refined) peanut oil
• Condiments and sauces (e.g., satay sauce, peanut sauce, mole sauce)
• Processed foods that may contain traces of peanuts (e.g., snack bars, breakfast cereals, cereal bars, chocolate, biscuits, nuts)
• Asian dishes (e.g., pad Thai, kung pao chicken, peanut curries)
• Salad dressings and dips containing peanut oil or peanut paste

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Soybeans

An allergy to soy is caused by an immune system reaction to the proteins found in soy. Soy, or soybeans, are a type of legume that is native to East Asia and grown for its edible bean. Soybeans are extremely versatile and processed to make a variety of food products, so it’s important to check ingredient labels of food products and ask about ingredients when dining out.

Soy allergy symptoms are like those of cow’s milk allergy. They can range from digestive issues like enterocolitis (inflammation of the digestive tract), to skin reactions and severe allergic reactions like anaphylaxis, although more rare. An allergy to soy is a risk factor for developing an allergy to other legumes, such as peanuts, green peas, lima beans, and string beans.¹

The food additive emulsifier and stabiliser soy lecithin and refined soybean oil can be safe to eat for people with a soy allergy because due to the processing steps and refining of these products most of the proteins that cause the allergic reaction are removed. However, allergic reactions to soy lecithin and refined soybean oil have been reported in sensitive individuals.¹ It’s best to consult your GP or allergy specialist in this case so your diet is not more restricted than it needs to be.

Foods to watch for with a soy allergy:³

• Edamame
• Cold-pressed soybean oil
• Soy-based products, such as tofu, tempeh, textured vegetable protein (hydrolysed vegetable protein), plant-based alternatives to meat, natto, soy drink, soy vegetable alternative to yoghurt, other dairy alternatives made from soy, soy margarine, miso, and kinako (roasted soy flour)
• Soy-derived ingredients, such as soy protein isolate, soy flour, soy starch, and soy lecithin
• Spreads, condiments and sauces (e.g., soy sauce, teriyaki sauce, sweet and sour sauce, Worcestershire sauce, stock cubes, gravies, sandwich spread, mayonnaise, salad cream)
• Baked goods and cereals (e.g., bread, breakfast cereals, cakes, biscuits, and snack bars)
• Processed and packaged foods (e.g., canned soups, ready meals, cold cuts, burgers, sausages, and hot dogs)
• Snacks and confectionary (e.g., crackers, flavoured chips, chocolate, and dessert mixes)
• Soy-based infant formula

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Milk

Milk allergy is an adverse immune system response to milk proteins (casein or whey) of different mammals, particularly cow, goat, sheep, and buffalo. There are broadly two types of allergic reactions to milk proteins. The first type happens very quickly – usually within two hours after eating foods that contain milk – and causes symptoms like skin rashes, stomach pain, breathing problems, or anaphylaxis. The other type takes longer to appear and mainly affects babies and young children. These reactions can cause stomach problems like vomiting, diarrhoea, cramps, and blood in the stool. In some cases, children with these allergies may struggle to gain weight properly.¹

Milk allergy and lactose intolerance are often mistaken for one another, but they have some differences. Milk allergy is an immune system reaction where the body mistakenly identifies milk proteins as harmful. People with a milk allergy should completely avoid milk, including cow, goat, and sheep.

In contrast, lactose intolerance is a digestive issue caused by the body’s inability to break down lactose, the natural sugar in milk, due to low levels of the enzyme lactase. Symptoms, including bloating, gas, and diarrhoea, develop gradually after eating dairy but are not life-threatening. Lactose intolerance can often be controlled by reducing dairy intake, choosing lactose-free alternatives, or taking lactase enzyme supplements.

It's estimated that cow’s milk allergy, the most common type of milk allergy, affects around 1% of children, and this often goes away as children grow older. About 0.5% of adults in Europe have a milk allergy.¹

Foods to watch for with a milk allergy:³

• Cow, goat, sheep, and buffalo dairy products, including lactose-free formulas (e.g., milk, cheese, butter, yoghurt, cream, buttermilk, sour cream, evaporated and condensed milk, paneer, haloumi)
• Milk-derived ingredients (e.g., whey, casein, caseinates, lactose, milk powder, milk solids, modified milk)
• Ghee
• Margarine
• Baked goods and cereals (e.g., milk bread, brioche, croissants, pastries, cakes, biscuits, pastries, crackers, breakfast cereals containing chocolate)
• Desserts and confectionary (e.g., ice cream, chocolate, custards, puddings, cream-based desserts, toffee, fudge)
• Processed and packaged foods (e.g., ready meals, processed meats, instant soups, ‘cream of’ soups, powdered sauces, meal replacement shakes, cheese flavoured foods)
• Spreads, condiments and sauces (e.g., cream-based sauces, white sauce, salad dressings, béchamel sauce, butter sauces, lemon curd, chocolate spread, seafood sauce, horseradish sauce)
• Beverages (e.g., some flavoured coffees, instant hot chocolate, protein shakes, malted drinks, milkshakes)
• Infant formula

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen. Plant-based products are often safe for people with milk allergies, but labels should always be checked for risk of cross-contamination.

Nuts

Someone with a nut allergy, also known as tree nut allergy, reacts to the proteins (e.g., vicilins, legumins, and 2S albumins) found in almonds, hazelnuts, walnuts, cashews, pecan nuts, Brazil nuts, pistachio nuts, shea nuts, and/or macadamia (Queensland) nuts. Although some foods contain the word ‘nut’ in their name, many are not part of the tree nut family and don’t need to be avoided. These include: coconut, nutmeg, chestnut, butternut squash, and pine nut.

Nuts are common triggers of systemic allergic reactions, which can be life threatening. It has been estimated that nuts are attributable to about one-third to one-quarter of all anaphylactic reactions attributed to food consumption. Even little amounts may cause severe allergic reactions.¹

An allergy to one type of nut is a risk factor for developing allergy to other types of nuts. This is because they contain similar allergenic proteins, a phenomenon known as cross-reactivity. Therefore, it’s often advised to avoid the entire nut group. Those with a tree nut allergy are also at a higher risk of developing a sesame allergy due to this cross-reactivity. Tree nuts belong to a different botanical family than peanuts, which are legumes. Therefore, having a tree nut allergy does not necessarily mean someone will also be allergic to peanuts, although cross-reactivities are more frequent. It’s important to consult a GP or allergy specialist to determine if peanuts can be safely included in the diet.¹

Some nuts are processed into nut oils. When they’re also refined during processing, most of the allergenic proteins are removed in the final product. Therefore, these are unlikely to cause an allergic reaction. In contrast, unrefined oils may contain still enough nut proteins to cause and allergic reaction and should be avoided by people who are allergic.

Foods to watch for with a nut allergy:³

• Unrefined, cold-pressed or un-processed nut oils (e.g., cold-pressed walnut oil)
• Nut butter (e.g., almond butter, cashew butter)
• Nut drink, nut vegetable alternative to yoghurt, other dairy alternatives made from nuts (e.g., almond drink, hazelnut drink, cashew drink)
• Bread, breakfast cereals, biscuits, pastries and cakes with nuts as ingredients (e.g., walnut bread, muesli, cereal bars, chocolate brownies, amaretto biscuits, macaroons, almond croissants, Bakewell tart, carrot cake)
• Confectionary, chocolates, and ice-cream (e.g., hazelnut spread, nougat, chocolates with nuts, marzipan, pistachio ice-cream)
• Plant-based meat alternatives (e.g., veggie burgers, nut roasts)
• Salads with added nuts or nut oils
• Pesto
• Marzipan
• Gluten-free foods with almond meal
• Almond food flavourings

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Celery

Celery is a vegetable from the Apiaceae family. People with a celery allergy react to the proteins in celery, which can cause allergic symptoms such as swelling and redness of the skin in the mouth and anaphylactic shock.¹

Some people react only to raw celery, as cooking can denature allergenic proteins. This process causes a chemical change in the conformation of the protein, resulting in the loss of its allergenicity. Others may be allergic to both raw and cooked celery, particularly if they have severe reactions.³

People with a celery allergy should also avoid the root vegetable celeriac as it’s closely associated with celery. Even when cooked, celeriac still can cause an allergic reaction.³

Foods to watch for with a celery allergy:³

• Celeriac
• Stock cubes and gravy granules
• Soups, stews, and broths
• Salads, dressings and sauces
• Spice mixes
• Condiments (e.g., Marmite)
• Crisps
• Tomato juice and smoothies

Mustard

Mustard allergy occurs when the immune system mistakenly identifies mustard protein as harmful and releases histamine, leading to allergic symptoms. White/yellow, black, and brown/oriental mustard are the main types of mustard seeds used in cuisine and food processing and can cause allergic reactions, including anaphylaxis.¹

Mustard allergy can sometimes develop in people who are already allergic to certain pollens. Mugwort-mustard allergy syndrome occurs when someone with hay fever reacts to mustard and related plants after being exposed to mugwort pollen.³

Foods to watch for with a mustard allergy:³

• All types of mustard (e.g., white, yellow, brown or black mustard seeds)
• Mustard greens (e.g., baby mustard, Chinese leaf mustard, Indian mustard, Kai Choi, Jie Cai, leaf mustard, Mostaza)
• Condiments and sauces (e.g., American style mustard, Dijon mustard, English mustard, French mustard, hot dog mustard, sweet mustard, wholegrain mustard, barbeque sauce, Cumberland sauce, curry sauce, ketchup, mayonnaise, honey & mustard sauce, salad dressings, salad oils, vinaigrettes, mustard oil)
• Processed deli meat, sausages, and meat that has a coating or marinade which contains mustard
• Stock cubes or liquid stock and spice blends (e.g., garam masala)
• Pickled onions, picked gherkins, pickles, chutneys, and piccalilli
• Chinese, Japanese, Indian, French, Middle Eastern, Eastern European, and Italian cuisines (e.g., Chinese hot and sour soup, Karashi, curries, dals, Béarnaise sauce, coq au vin, shawarma marinades)
• Mustard oil

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Sesame seeds

A sesame seed allergy is an immune system reaction to proteins found in sesame seeds, which can cause allergic symptoms, including anaphylactic shock.¹

A sesame allergy is different from peanut and tree nut allergies, although some people allergic to sesame seeds are also allergic to peanuts and tree nuts. It’s important to consult a GP or allergy specialist to determine whether peanuts and tree nuts can be safely included in the diet. People with a sesame allergy may also have a higher risk of allergies to other seeds, especially poppy seed.

Those allergic to sesame should carefully check ingredient labels, as sesame is widely used in breads and other bakery products, dressings, and international cuisines (e.g., Middle Eastern). Also, products that aren’t supposed to contain sesame may still have small traces of it due to how they are processed or handled during manufacturing and distribution.³

Foods to watch for with a sesame allergy:³

• Sesame oil
• Hummus
• Tahini (ground sesame seeds)
• Halvah
• Bakery products, biscuits, crackers, breadsticks, rice cakes, bagels, pies, and muesli
• Pre-packed delicatessen and processed foods (e.g., noodles, dips, soups, sausages, samosas, processed meats, veggie burgers, chutneys, salad dressings, mixed spices, spreads, and confection bars)
  

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Sulphur dioxide and sulphites

Sulphites are inorganic salts that can occur naturally in foods as a consequence of fermentation (e.g., of wine) and may be added to foods as preservatives or bleaching agents. Sulphites can trigger allergic reactions in sensitive individuals. When added to foods, sulphites help to prevent browning (e.g., of fresh fruits and vegetables, shrimps and raw potatoes) and have antimicrobial activity (e.g., in wine and beer), dough-conditioning properties (e.g., in frozen pies and pizza crusts), and bleaching effects (e.g., in maraschino cherries). All in all, sulphites help to maintain the freshness and flavour of foods and prolong its shelf-life.¹

Most people who have reactions to sulphites have sensitivity reactions. This type of reaction doesn’t involve the immune system so it’s not the same as an allergy, but it can cause allergy-type symptoms. Sulphites cause reactions by releasing sulphur dioxide, an irritant gas. When sulphite-containing foods mix with stomach acid, sulphur dioxide is released, which can irritate and constrict the airways. In sensitive individuals, this gas may travel back up into the airway, leading to symptoms such as wheezing, coughing, or breathing difficulties. This reaction is more common in people with asthma or respiratory conditions.³

If a product contains more than 10 parts per million (ppm) of sulphites, which is equal to 10 milligrams per kilogram or 10 milligrams per litre of sulphites, the words “contain sulphite” must be clearly stated on the label. You can also recognise sulphites on food labels by their E-numbers (E220 to E228, E150b, and E150d).⁷

Foods to watch for with a sulphite allergy:³

• Foods that contain the E-number E220 to E228, E150b and E150d
• Wine, including red wine, white wine, rosé, and organic and natural wines
• Dried fruits (e.g., dried apricots, prunes, golden raisins)
• Molasses
• Sauerkraut
• Bottled lemon juice and lime juice
• Dried potatoes
• Frozen potatoes
• Grape juice
• Wine vinegar
• Gravies
• Sauces
• Fruit topping
• Maraschino cherries
• Pectin
• Fresh shrimp
• Corn starch and corn syrup
• Maple syrup

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Lupin

Lupin is a legume from the same plant family as peanuts and soybeans. Someone who is allergic to lupin reacts to the proteins found in this food (conglutin), which can cause mild to severe allergic symptoms, including anaphylactic reactions.¹

Since lupin is closely related to peanuts, people with a peanut allergy have a higher risk of also being allergic to lupin. It’s important to consult a GP or allergy specialist to determine whether peanuts can be safely included in the diet.

Lupin can be processed to lupin flour which is more widely eaten food ingredient. Lupin flour is used in biscuits, pasta, sauces, and milk and soy substitutes. Lupin also has emulsifying properties and are used in the meat and cold-cut industry.

Foods to watch for with a lupin allergy:^1,3

• Baked goods (e.g., bread, pastries, gluten-free products)
• Pasta, especially in gluten-free or high-protein varieties
• Snacks (e.g., roasted lupin beans, crackers)
• Plant-based dairy alternatives made from lupin (e.g., lupin drink)
• Packaged soups, sauces, meat substitutes
• Plant-based egg substitute
• Cold-cut (lunch) meats (e.g., sausage, ham, meatloaf)

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Molluscs

Like crustaceans, molluscs are a type of shellfish. They’re invertebrates (they have no backbone), have a soft body inside, and some have a shell. Molluscs include abalone, clam, cockle, mussel, octopus, oyster, periwinkle, scallop, snail, squid (calamari), whelks, and sea urchin.³

People with a molluscs allergy react to the proteins of these foods. Molluscs allergies are different from fish allergies because the reactions commonly involve reacting to another protein. Tropomyosin is the primary allergenic protein in molluscs (and crustaceans, another type of shellfish), while parvalbumin is the main allergenic protein in fish. However, tropomyosin is also the main allergenic protein in tilapia fish.¹

If you’re allergic to one type of molluscs, it’s safer to avoid all types because the allergenic protein is found in many types of molluscs. Having a molluscs allergy also increases the risk of an allergy to crustaceans, since they’re both types of shellfish. It’s best to consult your GP or allergy specialist in these cases.¹ People who are highly sensitive may also need to avoid inhaling cooking vapours of these shellfish, for example in the home, near a food processing factory or catering outlet.³

Foods to watch for with a molluscs allergy:³

• Surimi
• Asian dishes (e.g., squid ink pasta, sushi, dim sum with oyster sauce)
• Sauces and broths made with shellfish stock
• Rice dishes such as paella, fried rice, and sushi rolls
• Stews, soups or casseroles such as seafood chowder, bouillabaisse, and cioppino
• Fish sauce and dishes that may include them, such as casseroles and stir-frys
• Dips or pates containing shellfish such as oyster pâté, scallop mousse, or clam-based spreads
• Fried foods cooked in shared oil with shellfish (e.g., fish and chips from a takeaway shop)
• Glucosamine supplements
• Some beer and wine which have been processed with shellfish

! This is not an exhaustive list, but it offers some ideas of foods likely to contain the allergen.

Can I eat foods that ‘may contain’ the allergen?

If you have a food allergy, seeing ‘may contain’ on a food label can be frustrating and confusing. Precautionary allergen labelling statements like ‘may contain [allergen]’ or ‘made in a factory that processes [allergen]’ are meant to warn consumers about the potential unintentional presence of allergens due to cross-contact during manufacturing.

The safest approach is to avoid foods with ‘may contain’ warning for your specific allergen, unless advised otherwise by a healthcare professional. The risk level varies depending on the food and manufacturing processes, but eating these foods could still cause an allergic reaction, even if the allergen is present in tiny amounts.

Precautionary allergen labelling is not legally regulated in the EU. The use of these warning statements is voluntary and varies between manufacturers. Often, these warnings are applied too broadly to ensure they cover all possible causes of allergies. There’s also an ongoing debate about the minimum amount of an allergen that should trigger labelling requirements, as trace amounts may or may not cause an allergic reaction in sensitive individuals. To address this, experts have been working on setting threshold doses – the smallest amount of an allergen that could cause a reaction in sensitive people. In the EU, discussions are ongoing to harmonise precautionary allergen labelling rules, so that labels provide clearer, science-based risk communication.⁸

Conclusion: staying safe with food allergies

EU law makes it mandatory for all packaged food to include information on any allergens it contains in its ingredients list. The 14 most common food allergens must be written using a special font, letter size, or background colour. For non-packaged foods, EU countries can adopt their own national rules on how to display allergen information. Outside of the EU food labelling laws will be different so it’s important to check ingredients carefully and ask for clarification.²

Managing food allergies requires more careful attention when preparing, handling, and eating foods. If you have a food allergy:⁹

• Read ingredient labels carefully, even for familiar products, as formulations may change. For foods that are not pre-packaged or foods prepared on-site (e.g., a café or restaurant), staff is required by law to provide information on the ingredients and possible allergens.
• Be cautious when eating out by asking restaurant staff about potential allergens in meals and risk of cross-contamination in the kitchen.
• Avoid cross-contamination by using separate utensils and cookware for allergen-free foods.
• Educate family, friends, and caregivers about specific allergies and emergency response procedures.
• Carry emergency medication (such as an epinephrine auto-injector) if prescribed by a doctor.
• Plan ahead when travelling or attending events, for example by taking safe snacks or meals yourself or by researching restaurants or food options beforehand to find allergy-friendly choices.