A practical test system for sensitive, rapid screening and authentication of peanut allergens in imported and exported food products in Chinese Customs

Abstract

Proper food allergen labeling protects consumers with serious food allergies, such as peanut (Arachis hypogaea) allergies. Currently, there is no widely accepted standard peanut allergen detection protocol for use by Customs agencies, which could avoid trade disputes caused by improper labeling. Herein we developed a peanut allergen screening and confirmation system for sensitive, rapid identification of peanut allergen ingredients which used gold immunochromatography assay strips followed by confirmatory western blotting. Gold immunochromatography assay strips were prepared with polyclonal antibodies against total peanut proteins for preliminary peanut allergen screening in foods labeled peanut-free. Western blotting with Ara h1-specific monoclonal antibodies was performed to confirm the results to exclude false positive results. Of 285 food samples tested, 164 were labeled as containing peanut allergens. The gold immunochromatography assay determined that 116 were negative, in accordance with their original labels. Five samples were positive, which was not consistent with their labels. These 5 positive samples were subjected to western blotting confirmatory tests. Only one was confirmed to be positive. We reported this result to the manufacturer and suggested they change the product label. This system, which includes sequential classification, screening, confirmation and reporting steps, was useful for monitoring peanut contamination in imported and exported foods by Chinese Customs.