GENEGEN TECHNOLOGY FOR DETECTION OF SALMONELLA SPP. AND GENUS LISTERIA/LISTERIA MONOCYTOGENES IN CHICKEN SAMPLES

Abstract

ABSTRACT Performances of two commercial test systems for the detection of Salmonella spp. and genus Listeria/Listeria monocytogenes (GeneGen Salmonella Detection Kit and GeneGen Listeria Detection Kit, respectively) were tested. The technology combines multiplex polymerase chain reaction with a shortened, simplified hybridization protocol using test strips. In specificity tests using a collection of over 80 bacterial strains representing 22 genera, no false positive or false negative results were observed. The limit of detection was 100 and 10 genome copies for the Salmonella and Listeria assays, respectively. The kits were used for both analyses of spiked and naturally contaminated chicken samples, and their performances were compared with standard methods. An amount of 1–10 cfu/25 g of the respective pathogen added could be detected. Results achieved with the GeneGen Salmonella Detection Kit were in 100% concordance with the microbiological protocol. The GeneGen Listeria Detection Kit proved to be more sensitive than the standard method in the spiking experiments, as well as for chicken samples naturally contaminated with both Listeria innocua and L. monocytogenes. The kits provided a time saving of several days compared to conventional methods (30‐h detection time for Salmonella, 30–54 h for Listeria). The protocol is simple and does not require any high‐tech equipment for evaluation or documentation after DNA amplification. Hybridization can be carried out at ambient temperature, and results are evaluated with the unaided eye. Thus, these kits could be a valuable tool for the screening of food samples and confirmation of suspect colonies, especially in modestly equipped laboratories.