A novel real-time polymerase chain reaction-based method for the detection and quantification of lactose-fermenting Enterobacteriaceae in the dairy and other food industries

Abstract 

The presence of lactose-fermenting Enterobacteriaceae and coliforms is routinely assessed to determine the hygienic quality of water and foods, particularly dairy products. This paper reports the use of lacZ-specific primers in an SYBR green I-based real-time PCR method for the easy and rapid detection of coliforms in dairy products. A large number of bacterial species were assayed to establish the specificity of the method. The sensitivity of the method was assessed using artificially contaminated cheeses. The limit of detection was 1 coliform cell in cheese samples enriched for 8h in a culture medium. The entire procedure, including sample processing, enrichment, DNA extraction, and real-time PCR amplification, can be completed within 10 to 12h, making it a single-day assay.

Key words: Enterobacteriaceae, coliform, real-time polymerase chain reaction detection, cheese