Evaluation of Real-Time PCR to complement ISO 6579:2004 method for the detection of Salmonella in pork cuts

Abstract

According to Commission Regulation (EC) No 2073/2005 of 15 November 2005 on microbiological crite-ria for foodstuff , the analytical reference method for the detection of Salmonella in food is ISO 6579:2004. However this long and labor-intensive method is not in line with the short production times of the food industry. In the last years, Real-Time PCR is used more and more by scientists for the relia-ble, fast and specific detection of bacterial pathogens in food. The aim of the present study was to eval-uate the Salmonella detection capability of a validated Real-Time PCR assay on naturally contaminated pork cuts in comparison with the reference method ISO 6579:2004. Three sampling were performed and included 16 pork cut packaging. From each packaging, three aliquots of 10 g each were tested separate-ly by ISO 6579:2004 method and by Real-Time PCR. In particular this molecular method was applied on DNA samples extracted from pre-enrichment broth after 1 and 18 hours of incubation. Within the three sampling periods, Real-Time PCR detected Salmonella in 81%, 100% e 62,5% of pork cut samples respectively, whereas the corresponding percentages of detection of the reference method were 56%, 81% e 62,5% respectively. In conclusion the Real-Time PCR assay used in the present study might be a reliable tool for a fast detection of Salmonella on pork cuts, especially when large number of samples needs to be tested. The reference method might be applied only on positive samples for isolation purpos-es mandatory in epidemiological investigations.

Keywords

• According to Commission Regulation (EC) No 2073/2005 of 15 November 2005 on microbiological crite-ria for foodstuff , the analytical reference method for the detection of Salmonella in food is ISO 6579:2004. However this long and labor-intensive method is