Sample preparation methods for PCR detection of Escherichia coli O157:H7, Salmonella typhimurium, andListeria monocytogenes on beef chuck shoulder using a single enrichment medium

Detection ofSalmonella entericaSerovar Typhimurium by Using a Rapid, Array-Based Immunosensor

“…However, many of these LODs represent the concentrations of inoculum used rather than actual bacterial counts after enrichment; postenrichment concentrations can reach 10 6 to 10 9 CFU/ml (6,7,17,23). Detection limits determined in studies reporting LODs based on postenrichment cell densities are in the range of 10 3 to 10 6 CFU/ml (5,6,17), comparable to the LOD determined for this study. A PCR system able to detect Salmonella in a carcass rinse sample without pre-enrichment has recently been described (30); the LOD reported (10 2 to 10 4 CFU/cm 2 ) is comparable to that obtained for the MAAB (2.7 ϫ 10 3 CFU/ cm 2 ).…”

“…Thus, a pre-enrichment step is typically required to increase the number of viable cells while effectively diluting inhibitory substances present in the sample. A large number of papers describing PCR-based detection of Salmonella from spiked or naturally contaminated foods have claimed LODs ranging from 0.1 to 100 CFU/g (6,10,31,37,40). However, many of these LODs represent the concentrations of inoculum used rather than actual bacterial counts after enrichment; postenrichment concentrations can reach 10 6 to 10 9 CFU/ml (6,7,17,23).…”

“…A large number of papers describing PCR-based detection of Salmonella from spiked or naturally contaminated foods have claimed LODs ranging from 0.1 to 100 CFU/g (6,10,31,37,40). However, many of these LODs represent the concentrations of inoculum used rather than actual bacterial counts after enrichment; postenrichment concentrations can reach 10 6 to 10 9 CFU/ml (6,7,17,23). Detection limits determined in studies reporting LODs based on postenrichment cell densities are in the range of 10 3 to 10 6 CFU/ml (5,6,17), comparable to the LOD determined for this study.…”

“…The results described here indicate that the MAAB not only has similar or better detection limits than other sensors, but also requires only 15 min for analysis of prepared samples. Sample processing is simple, requiring only homogenization of the foodstuff or excreta, followed by coarse filtration or centrifugation; this ease of sample preparation contrasts greatly with the large numbers of manipulations typically required for nucleic acid-based techniques (6,10,31), even with immunomagnetic separation.…”

Development of a multiplexed PCR assay combined with propidium monoazide treatment for rapid and accurate detection and identification of three viable Salmonella enterica serovars

“…Various detection methods have been developed to microorganisms especially pathogens associated with human illnesses in food matrices (Bhaduri & Cottrell, 2001;Chen, Wang, Beaulieu, Stein, & Ge, 2011;Hagren et al, 2008;Rigby, 1984;Zhao et al, 2009). A major drawback of using enriched culture is the impossibility to detect viable-but-non-culturable (VBNC) cells (Wang, Li, & Mustapha, 2009).…”