Extraction of Staphylococcal Enterotoxins (SE) From Minced Meat and Subsequent Detection of SE with Enzyme-Linked Immunosorbent Assay (ELISA)

Abstract

ELISA (enzyme-linked immunosorbent assay) was employed to demonstrate staphylococcal enterotoxins A, B, C and E (SEA, SEB, SEC and SEE) in minced meat (50% beef/50% pork). For unheated minced meat, extraction of the sample with an equal amount of distilled water at pH 4.5 and a subsequent concentration (10-fold) of the extract, readjusted to pH 7.2, was sufficient to detect less than 0.5 μg of SE per 100 g of product. The extraction procedure gave 40–80% recovery of the toxin, and using the ELISA system neither false-positive nor false-negative results were obeserved. Using the just mentioned extraction procedure, recovery of SE that had been heated in minced meat was low (0.14% for SEB). It was demonstrated that components extracted by heating (among others, gelatin) present in minced meat caused immunological inactivation of SEB, SEC and SEE during heating. From monkey-feeding tests it became clear that the immunological inactivation of SEB in gelatin by heating was accompanied by biological inactivation.