Purpose: The study compares this alternative method to the ISO 11290-1/A1:2004 Reference method for the detection of Listeria spp. in food and environmental samples.
Methods: A unique protocol has been developed for next day detection. For each of five food categories, 60 samples of 25 g were tested by both methods. For larger sample size (125 g, Mexican Soft Cheese), 30 samples were tested. This new method consists in a single enrichment in LPT broth incubated 22 h at 37°C. Then, DNA is extracted using mechanical lysis in a dedicated lysis tube: 15µl are introduced through a specifically designed cap that does not require any tube or cap handling. Extracted DNA is used directly with freeze dried PCR reagents. The PCR method is based on dual probe detection (Fluorescence Resonance Energy Transfer) allowing real time detection and melting curve analysis. The call is positive when it combines an amplification curve and a melting peak allowing a strong specificity of the test. Co-detection of Listeria monocytogenes is possible using same extracted DNA with GENE-UP® Listeria monocytogenes PCR kit.
Results: Methods were compared following ISO16140 guidelines. The comparison did not show any statistical difference on the 90 samples tested.
Significance: GENE-UP® Listeria spp. method enables a reliable and rapid detection of Listeria spp. in food and environmental samples including a user-friendly workflow.