Rapid detection for low numbers of Escherichia coli O157:H7 by real-time PCR in cabbage using a combination of filtration, short microbial enrichment, and DNA concentration within 4 h

Methods: focused on conventional foodborne pathogen detection by selective media are cumbersome and require long time for culture enrichment. Several rapid tests have been developed for the detection of Escherichia coli O157:H7 in the food industry. However, the E. coli O157:H7 method takes very long and requires more than one day to achieve the detection threshold using PCR based enrichment in food. We reported a combination of filtration-based accelerated sample concentration methods to detect <9 CFU/25g of E. coli O157:H7 in cabbage. Filtration, short concentration, as well as DNA concentration contribute to making the detection level the target for real-time PCR analysis. The short enrichment was performed after the filtration, which was shorter than the conventional enrichment method. It was concluded that 0-7 CFU/25 g of E. coli O157:H7 was detected within 4 h after 2 h of incubation following filtration. This combination of filter-based enrichment methods is a faster and more efficient way for reaching the desired bacterial concentration compared to the conventional culture enrichment steps, and can significantly reduce the time required to obtain assay results.