Comparative detection of Salmonella enterica in meat by 3M Molecular Detection Assay Salmonella and the ISO 6579:2002 method.

Introduction: Salmonella spp. is a zoonotic microorganism responsible for the second most common food-borne disease in the European Union. Purpose: The purpose of this study was the comparative detection of Salmonella enterica in meat products by the 3M Molecular Detection Assay Salmonella and the ISO 6579:2002 method. Methods: A total of 200 meat samples (raw meat from chicken, turkey, pork and beef, minced meats, sausages, offal and meat preparations) were tested. After pre-enrichment in BPW (37±1°C for 16-20 h) broth cultures were tested by: i) the 3M method employing a prototype machine; ii) the ISO 6579:2002 cultural method. Samples positive by the 3M method were subjected to a three-tube MPN enumeration method. Twenty-five grams per sample were diluted 1:10 in BPW. The three-tube MPN dilutions represented 1.0, 0.1, and 0.01 g of the samples. Results: Overall, 22 samples out of 200 (11.0%) were found positive for Salmonella spp. Fifteen samples were positive by both methods (68.2%); three more samples were found positive by the 3M method only and four by the ISO 6579 method only. One of the four samples testing positive by the ISO method only was found to be inhibited by the 3M method. Positive and negative results were available after 24 h using the 3M method while the ISO 6579 method required three days for negative results and five-seven days for positive ones. Salmonella enumeration ranged from <0.3MPN/g to 2.1 MPN/g. Significance: The 3M Molecular Detection Assay Salmonella is a time saving and easy to use method that can be very useful in processing food samples. Discordant results between the two methods could be attributable to the low level of contamination by Salmonella spp. in these naturally contaminated samples which implies stochastic randomness in the positive outcome of any low contamination sample regardless of the method used.