Simple and rapid detection of Listeria monocytogenes in fruit juice by real-time PCR without enrichment culture

We developed a simple, rapid procedure for the detection of Listeria monocytogenes in unpasteurized fruit juice using real-time PCR without enrichment culture. PCR inhibitors were removed from fruit juices using Chelex resin followed by gel filtration with a Sephadex column. The purification step can be completed in 20 min, and purified juice samples can be used directly as PCR templates without further dilution. PCR conditions were optimized and maximum sensitivity (ca. 1 cell/reaction) was achieved. This convenient method should prove useful for high-throughput surveillance of L. monocytogenes as well as other food-borne pathogens that may contaminate fruit juices.