Mustard is one of the 14 major allergen groups within foods. This needs to be mentioned either on a label or on a menu when it is an ingredient in food as per EU food labelling regulations. Often mustard is a masked or hidden allergen within foods as it can be not obvious of its presence by sight, taste or smell. Mustard has been found to be more prevalent in countries which have mustard as a key ingredient in the diet such as France. However, it can be used in many styles of cooking such as (but not limited to) Chinese, Japanese, Indian, French, Middle-Eastern, Eastern-European and Italian. In the UK due to limited research into mustard as an allergen, it is unknown how common it is or how many people are currently suffering from an allergy to mustard.
Mustard allergy has been a common allergen for a number of years, it is seen as on the increase however with spices (including mustard) becoming more popular within foods, therefore increasing the likelihood of being exposed to it in a regular diet. It can also be used as an added ingredient in processed foods (even baby food) which highlights the importance of identifying ingredients of a food using the labelling.