A simple and fast detection method for bovine milk residues in foods: a 2-site monoclonal antibody immunochromatography assay.

UNLABELLED: The ingredient declaration on food labels assumes paramount importance in the protection of food-allergic consumers. China has not implemented Food allergen labeling. A gold immunochromatography assay (GICA) was developed using 2 monoclonal antibodies (mAb) against the milk allergen β-lactoglobulin in this study. The GICA was specific for pure milk samples with a sensitivity of 0.2 ng/mL. Milk protein traces extracted from 110 food products were detected by this method. The labels of 106 were confirmed by our GICA method: 57 food samples originally labeled as containing milk were positive for β-lactoglobulin and 49 food samples labeled as not containing milk were negative for β-lactoglobulin. However, 3 food samples falsely labeled as containing milk were found to contain no β-lactoglobulin whereas 1 food sample labeled as not containing milk actually contained β-lactoglobulin. First, these negatives could be because of the addition of a casein fraction. Second, some countries demand that food manufacturers label all ingredients derived from milk as "containing milk" even though the ingredients contain no detectable milk protein by any method. Our GICA method could thus provide a fast and simple method for semiquantitatation of β-lactoglobulin in foods. PRACTICAL APPLICATION: The present method provides a fast, simple, semiquantitative method for the determination of milk allergens in foods.