A customer orders a ham sandwich with lettuce tomatoes and mustard on whole wheat bread and which food in the sandwich is considered a common food allergen

Answer:Gluten protein in sandwich is considered as a common food allergen. Step-by-step explanation:Sandwich is made of wheat. The wheat cereal is considered as the common food allergen due to the presence of the protein gluten. This allergy can cause vomiting and rashes.Some individuals are sensitive to the gluten protein present in the wheat. The reaction due to the presence of gluten can be fatal for the individual. The individual may suffer from abnormal immune reactions in the body. Skin testing can be used to diagnose the wheat allergy.