Comparison of the sensitivity of the Gene-Up® and ANSR Listeria Right NowTM assays and the influence of swab type when detecting Listeria monocytogenes in the environment with a dairy context

This study tested the Gene-Up® protocol for Listeria and the Listeria Right Now™ environmental test for their abilities to detect dairy-related Listeria monocytogenes when present on stainless steel surfaces. Different swabbing materials were tested to evaluate whether they affected the detection capability of these methods. The swab used in the ANSR Listeria Right Now™ assay recovered 2% of L. monocytogenes inoculated on a surface, while other swabs recovered up to 10%. The ANSR Listeria Right Now™ assay detected 1 cfu, and the Gene-Up® method detected 10 cfu of L. monocytogenes when media was directly inoculated (without using swabs). When swabs were used the sensitivities of both assays were similar. This study showed that both the recovery percentage of L. monocytogenes from surfaces by swabs and the in-assay sensitivity contribute toward the overall sensitivity of methods used to detect L. monocytogenes from surfaces in the dairy context.