BACKGROUND: Accidental allergic reactions to food are frequent, can be severe and even fatal. OBJECTIVE: To analyze the culprit food products and levels of unexpected allergens in accidental reactions.
METHODS: A prospective cohort study was conducted in adults (n=157) with a physician-confirmed diagnosed food allergy. During a 1-year follow up, 73 patients reported accidental allergic reactions and the culprit food products. Food samples received (51) were analyzed for a wide range of suspected non-ingredient allergens and the risk was quantified. RESULTS: A very diverse range of food products was responsible for the unexpected allergic reactions. Thirty-seven percent (19/51) of products analyzed had 1 to 4 culprit allergens identified that were not supposed to be present according to the ingredient declaration. Concentrations varied from 1 to 5000 mg protein of the allergenic food per kg food product, and were highest for peanut, milk and sesame. Milk proteins posed the highest estimated risk for objective allergic reactions. The intake of culprit allergens by patients varied considerably. For these cases in which culprit allergens were detected, the intake of at least one allergen exceeded the reference dose or a culprit allergen with a yet unknown reference dose was present. Both patient neglect of PAL statements and omission of using a PAL statement by food manufacturers seem to contribute to accidental reactions. CONCLUSION: A wide range of food products are causing accidental reactions in food allergic patients. Eight different allergens not declared on the ingredient lists were detected in the culprit food products, all representatives of the allergens regulated in the EU.