Establishment and application of colloidal gold immunochromatographic method for rapid detection of major allergen tropomyosin in crustacean aquatic products

Currently, food allergy has become a food safety issue of global concern, and there is no effective cure at home and abroad. Avoiding the intake of allergens is the best solution to prevent food allergies; therefore, the construction of a rapid and sensitive allergen detection system is of great research significance to ensure the safety of consumers. A colloidal gold immunochromatographic method was established with tropomyosin (TM) of Litopenaeus vannamei as the detection target for the rapid detection of major allergens TM in crustacean aquatic products. SD rats and New Zealand rabbits were immunized with natural TM to prepare polyclonal antibodies. Then, the immunochromatographic test strips were assembled based on the double antibody sandwich principle using 40 nm colloidal gold labeled rat anti-TM IgG as detection antibodies and rabbit anti-TM IgG as capture antibodies for the detection of commercial food samples. The test strip can display the results within 5 min with a 10 ng/mL visual detection limit. The developed immunochromatographic test strips showed high specificity to crustacean, such as shrimp, crab, Procambarus clarkii and Homarus americanus, although there is a weak cross reaction with clams and scallops. The recoveries of standard addition in commercial food products without crustaceans were 81%-126%, indicating the method's high accuracy. The intra-and inter-batch coefficient of variation of the test strip was less than 15%. Additionally, the test results of the actual food samples were consistent with the food allergen label. The results show that the developed method possesses sufficient sensitivity and specificity. Therefore, it can effectively detect crustacean residues in a variety of matrices and commercial food samples and has strong practical application value.