Purpose: The purpose of the study was to compare the performance of the 3M MDS against the ISO 6579:2002 e ISO 11290-1 reference methods for detection of Salmonella, Listeria spp. and Listeria monocytogenes in a variety of food matrices typical of the dairy industry within the Santa Fe region in Argentina.
Methods: Food samples from a variety of dairy matrices were artificially inoculated with overnight cultures of Salmonella Typhimurium ATCC 14028 or Listeria monocytogenes ATCC 19114. A total of 47 samples were analyzed for Salmonella spp., 27 for Listeria spp. and 32 for Listeria monocytogenes. Samples were enriched by combining 25 g with 225 ml of media and incubating for 18 - 24 h at 37°C for Salmonella spp., or for 24 - 28 h at 37°C for Listeria spp. and Listeria monocytogenes. Samples were analyzed by either the 3M MDS and ISO 6579:2002 or ISO 11290-1 reference protocols.
Results: All artificially inoculated samples were detected as positive by the 3M MDS after 15 min. The non-inoculated samples were detected as negative by the 3M MDS and confirmed to be free of the pathogen via culture method. The results reflect 100% accuracy, inclusivity and exclusivity, with no false positives or false negatives observed and excellent correlation with the corresponding ISO methodologies.
Significance: Results demonstrate the suitability of the 3M MDS for rapid analysis of dairy food matrices, allowing full confidence in the release of ingredients and finished products based on timely and highly accurate results.