Purpose: During the validation study conducted by the ISHA (Alpa Group, Massy, FRANCE), a sensitivity study was performed comparing this alternative method to the ISO 11290-1/A1:2004 Reference method for the detection of Listeria in 6 categories of food and environmental samples. The objective was to compare the alternative method to the ISO 11290-1/A1:2004 Reference method for the detection of Listeria in food and environmental samples.
Methods: For all categories (including meat products, dairy products, seafood, vegetables, composite foods and environmental samples), 551 samples of 25g were tested by both methods. This new method consists in a single enrichment in LPT broth incubated 22h for food samples and 18h for environmental samples at 37°C. Then, DNA is extracted using mechanical lysis in a dedicated lysis tube: 20µL are introduced through a 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.
Results: Methods were evaluated following the new ISO 16140-2 guidelines. The GENE-UP® Listeria sp method shows similar results to the ISO 11290-1/A1:2004 Reference method for the detection of Listeria.
Significance: GENE-UP® Listeria sp method enables a reliable and rapid detection of Listeria spp. in a variety of food : 22h enrichment, including a user-friendly workflow.