Microbial contamination in foods could lead to illnesses and substantial losses in both food industry and public health sectors. Rapid detection of microbial hazards (i.e., pathogens, hygiene indicator microorganisms) can accelerate surveillance and diagnostic processes reducing transmission and minimizing undesirable consequences. This study developed a multiplex PCR (m-PCR) for the detection of six common foodborne pathogens and hygiene indicators using specific primers for uidA of Escherichia coli, stx2 of Escherichia coli O157:H7, invA of Salmonella spp., int of Shigella spp., ntrA of Klebsiella pneumoniae, and ail of Yersinia enterocolitica and Yersinia pseudotuberculosis. Sensitivity of the m-PCR was 100 fg or ∼20 bacterial cells. Each primer set amplified only the targeted strain, and specificity was demonstrated by lack of nonspecific bands with DNA from 12 other bacterial strains. Following ISO 16140-2:2016, the relative limit of detection of the m-PCR was comparable to that of the gold-standard method; however, the processing time was five times faster. The m-PCR was applied to detect the six pathogens in 100 natural samples (50 pork meat and 50 local fermented food samples) and compared to results of the gold-standard method. Positive cultures for Klebsiella, Salmonella, and E. coli were 66%, 82%, and 88%, respectively, of meat samples and 78%, 26%, and 56%, respectively, of fermented food samples. Escherichia coli O157:H7, Shigella, and Yersinia were not detected in any of the samples by both standard and m-PCR methods. The developed m-PCR assay showed comparable results with the traditional culture technique proving its rapid and reliable detection of six foodborne pathogens and hygiene indicators in food.
Keywords: Enterobacterales; foodborne pathogen; microbial hazards; multiplex PCR.