A COMPARATIVE-STUDY OF THE GENE-TRAK LISTERIA ASSAY, THE LISTERIA-TEK ELISA TEST AND THE FDA METHOD FOR THE DETECTION OF LISTERIA SPECIES IN RAW-MILK

A total of 110 raw milk samples were analysed using the Gene-Trak Listeria assay, unmodified and with four modifications to its enrichment procedure, the Listeria-Tek ELISA test and the FDA method. Thirty-five samples yielded confirmed positive results by at least one of the methods tested. The original Gene-Trak protocol yielded 24 confirmed positive results, significantly higher than the 13 obtained with the Listeria-Tek ELISA test or with the FDA method. The modifications to the Gene-Trak Listeria assay did not significantly increase the detection rate of Listeria spp.