The effects of curing and cooking on the detection of species origin of meat products by competitive and indirect ELISA techniques

Abstract

The purposes of this study were: (1) to develop and compare competitive and indirect enzyme linked immunosorbent assay (ELISA) methods for detecting species specific albumins in meat samples and (2) to examine the effect of curing and cooking on the identification of species origin of meats. Commercially obtained rabbit anti-pig serum albumin (anti-PSA) and rabbit anti-sheep serum albumin (anti-SSA) were affinity purified, and used to develop competitive and indirect ELISA procedures for PSA and SSA. The competitive ELISA procedures showed the lowest cross-reactivity with related serum albumins. Both ELISA procedures were capable of detecting as little as 5% pork or sheep in beef. Curing resulted in little or no inhibition in the ability of ELISA procedures to detect pork or sheep in beef. Cooking completely eliminated the ability of the competitive PSA ELISA to detect pork in beef, and of both SSA ELISA procedures to detect sheep in beef. Cooking also greatly reduced, but did not eliminate, the ability of the indirect PSA ELISA to detect pork in beef. Curing and cooking essentially eliminated the ability of the PSA ELISA procedure to detect pork in beef. Curing and cooking resulted in a 70 to 74% decrease in the signal of sheep meat in SSA ELISA procedures. These results demonstrated that competitive and indirect ELISA procedures are capable of determining the species origin of raw and cured meat. Heating raw or cured meats greatly reduced, but did not always eliminate, the ability of ELISA procedures to detect species origin of meats.