LACTATE-DEHYDROGENASE AS SAFE END-POINT COOKING INDICATOR IN POULTRY BREAST ROLLS - DEVELOPMENT OF MONOCLONAL-ANTIBODIES AND APPLICATION TO SANDWICH ENZYME-LINKED-IMMUNOSORBENT-ASSAY (ELISA)

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to detect lactate dehydrogenase (LDH) as a marker protein for verifying endpoint cooking of uncured poultry products. Monoclonal antibodies were prepared against chicken muscle LDH and used with rabbit polyclonal antibodies developed against turkey or chicken muscle LDH for capture and detection in the assay, respectively. Minimum assay detection limits for turkey and chicken muscle LDH were 1 ng/ml. Turkey and chicken muscle LDH, but not LDH from other species cross reacted in the ELISA. The ELISA was further verified using extracts of turkey breast rolls processed to internal temperatures between 68.3 and 72.1-degrees-C. The LDH content of extracts diluted 3- to 6-fold was below 15 ng/ml for turkey rolls processed to 70.9 and 72.1-degrees-C. At a 6-fold dilution, LDH content of extracts from rolls processed to 69.7-degrees-C was approximately 10 times greater than those processed to 70.9-degrees-C. A survey of market precooked poultry products indicated assay validity with precooked turkey roast, but not turkey hams with maximum internal temperature requirements of 68.3-degrees-C. Results suggested the sandwich ELISA should be applicable for determining whether turkey breast rolls are processed to the required U.S. Department of Agriculture endpoint temperature of 71.1-degrees-C.