Requires food products that do not contain specific ingredients

An enzyme deficiency in the body that prevents the digestion of lactose, gluten and salicylates

Common allergies include: peanuts, tree nuts, milk, eggs, sesame seeds, fish, shellfish, soy and wheat

Added ingredients including food additives and processing aids may also be the cause of food intolerance

Modern food-processing techniques can create food safety issues if machines are used to produce multiple products with varying ingredients

Symptoms: rashes, asthma, bowel issues, colic, bloating, migraines, lethargy, irritability

This can potentially cause contamination of foods without allergen ingredients

People with peanut and nut allergies are at the greatest risk of fatal allergic reactions

Symptoms: hives, swelling of mouth and throat preventing regular breathing, vomiting or diarrhoea, collapse and in most severe cases anaphylaxis

Food intolerance can be difficult to diagnose meaning it is difficult to prevent