Rapid and sensitive detection of E. coli O157:H7 and S. Typhimurium in iceberg lettuce and cabbage using filtration, DNA concentration, and qPCR without enrichment

The outbreaks due to the low number of foodborne pathogens present in ready-to-eat products can be prevented by rapid and sensitive detection method. However, as a conventional detection method, it is impossible to monitor foodborne bacteria existing which is less than 50 cfu/25 g in a food. This study was designed to investigate the possibility of detecting 1 cfu in the short-term through filtration, DNA concentration, and qPCR. As a result of the filtration + DNA concentration method, the recovery concentrations of Escherichia coli. O157:H7 and Salmonella Typhimurium was not significantly different from initial inoculation (> 7 cfu/25 g). In iceberg lettuce and cabbage, this method was able to detect 7 and 7 cfu/25 g of E. coli. and 68 and 5 cfu/25 g of S. Typhimurium. We demonstrated the potential of the filtration + DNA concentration method as a shorter time alternative to conventional enrichment-based rapid detection in vegetables.