Assessment of food safety using a new real-time PCR assay for detection and quantification of virulence factors of enterococci in food samples

Aims: Development of Taqman MGB real-time PCR (q-PCR) assays for the quantitative detection of virulence factor genes in pure culture and food samples with regard to food safety assessment. Methods and Results: New Taqman primers and probes were designed for the ace, esp and gelE genes based on the determinants of virulence profiles of enterococcal strains from GenBank. The high specificity and accuracy of the Taqman probe assay was confirmed. The limit of detection for the different virulence genes was 102 CFU ml−1 or CFU g−1 for pure culture and meat samples, and 103CFU g−1 for cheese samples. Conclusion: This method provides the specific and rapid detection and quantification of ace, esp and gelE genes compared to conventional PCR assays, thus allowing the rapid and direct safety assessment of Enterococcus genus in food samples. Significance and Impact of the Study: This study presents efficient methods that can be used directly on food products for the rapid quantification and tracing of virulence genes, regarding food safety assessment. Moreover, this is the first study to quantify these virulence factors using a specific Taqman q-PCR assay in food samples.