Immunodetection of finfish residues on food contact surfaces

Finfish is one of the major allergenic foods, whose declaration is required on packages. Undeclared allergenic residues are mainly derived from allergen cross-contact. Swabbing of food contact surfaces helps to detect allergen cross-contamination. This study aimed to establish a competitive enzyme-linked immunosorbent assay (cELISA) to quantify the major finfish allergen, parvalbumin, from swab samples. First, parvalbumin from four finfish species was purified. Its conformation was investigated under reducing, non-reducing and native conditions. Second, one anti-finfish parvalbumin monoclonal antibody (mAb) was characterized. This mAb had a calcium-dependent epitope which was highly conserved in finfish species. Third, one cELISA was established with a working range between 0.59 ppm and 150 ppm. It showed a good recovery of swab samples on food-grade stainless steel and plastic surfaces. Overall, this cELISA could detect a trace amount of finfish parvalbumins on cross-contact surfaces, which is suitable for allergen surveillance in the food industry.