Food allergens

Teacher's reference notes on food safety, food allergies and intolerances.

Allergies and intolerances

  • If someone has a food allergy, their immune system reacts to a particular substance in a food that other people find harmless. Most allergic reactions are mild and symptoms include raised itchy red skin rash and swelling of the face. However, severe allergies may cause a reaction called anaphylaxis (or anaphylactic shock) which can be fatal if not treated immediately.
  • Food intolerance is different from allergy since it does not involve the immune system and thus is not generally life-threatening.
  • There are 14 substances or products causing allergies or intolerances that must be identified when present in food. They are:
    • Celery, Cereals containing gluten, crustaceans (e.g. prawns and crabs), eggs, fish, lupin (seed and flour), milk, molluscs (e.g. mussels, oysters), mustard, nuts, peanuts, sesame seed, soybeans, sulphur dioxide & sulphites (over 10 mg/kg or 10 mg/l).
    • Download the allergy poster


Prepacked foods

  • Always read the ingredients list on any prepacked food you buy to make sure it doesn’t contain the foodstuff you must avoid.
  • The allergens listed above must be emphasised in the ingredient list to highlight their presence so they stand out from the other ingredients. Allergy advice boxes can only be used to indicate where allergen information may be found on the label and/or how the allergens have been emphasised.
  • Sometimes small amounts of an allergen may get into a product by accident, even though food producers take great care to stop this happening. If there is a risk this could happen, the label might say something like ‘may contain [name of allergen]’. These warnings should be taken seriously.
  • Check information on food bought online. Sometimes the online information might not be up to date, so always check the label when the food is delivered.
  • Most of the major supermarket chains sell a range of products that are free from particular foods or ingredients (such as wheat, gluten or dairy products). Remember you don’t have to buy specialist foods. Lots of normal foods won’t contain the food you are trying to avoid.
  • Please note that the foodstuffs listed above have been identified as causing most food allergy problems throughout the EU. However, some people may be allergic to other foods (e.g. kiwi fruit, rapeseed oil). When used as deliberate ingredients in prepacked foods, their presence must be noted in the ingredient list but they will not be emphasised. Anyone with a food allergy must read ingredient lists carefully.

Foods sold non-prepacked

  • Ask the person serving for information about the foods that don’t have labels. Foods that aren’t prepacked, such as bread from a bakery, salads or cold meats from a deli counter, might be sold in a wrapper but they don’t have to be labelled. However, allergen information must be available for all food sold loose/non-prepacked including food served by caterers. The food business must inform customers how this information can be obtained (e.g. display a poster to say allergy advice is available from members of staff).
  • Beware of accidental contact with food you need to avoid. Small amounts of the allergen may come into contact with the food you wish to buy e.g. from being next to it, or from using the same knife or spoon, or from being wrapped in paper that has touched another food. This is a particular problem with seeds and nuts, which can fall off baked items, and at deli counters, where little pieces of food can drop into another bowl.
  • Look out for ‘hidden’ ingredients. Biscuits and cakes might contain hidden nuts e.g. almonds in marzipan, ground hazelnut might be in chocolate and icing can contain egg.

Eating out

  • When you book a table at a restaurant, inform them about your food allergy or intolerance to ensure they can provide you with a meal that doesn’t contain the food or ingredient you react to.
  • When you arrive at a restaurant, make sure the waiting staff are aware of your allergy or intolerance and how serious it is. Read the menu carefully to see if there is any mention of the food you react to in the name or description of a dish.
  • Ask staff to check with the chef about allergens or order something else.
  • Remember that meals aren’t always made the same way. If you have eaten a particular dish in one restaurant, don’t assume it will be ok the next time or in a different restaurant. Always ask about the dishes.
  • Be careful when using self service areas in restaurants/cafés where food is in open containers. Even though dishes might not contain the food you react to, it’s easy for a small amount to get into a dish accidentally, either because containers are next to each other, or because people use the same tongs or spoons for different dishes.

Allergen alerts

  • When the allergy information on food labels is missing or incorrect, or if there is some other allergy risk, the affected foods need to be withdrawn from sale.
  • When this happens, Food Standards Scotland will issue allergy alert. If you want to know when a food has been withdrawn because of a food allergy risk, you can sign up to our free allergy alert service:

Food allergies

Most allergic reactions to food are mild, but some can be very serious. A small amount of the food concerned can trigger a reaction.

More on this topic


Allergy Poster

Download a poster detailing the 14 major allergens that must be mentioned when used as ingredients on food.