Validation of the RapidChek® Listeria NextDay™ Plus Test System for Detection of Listeria Spp. in Matrices: Hot Dogs, Frozen Cooked Breaded Chicken, Vanilla Ice Cream, Stainless Steel, Plastic, Rubber, and Painted Concrete Surfaces.

BACKGROUND: Listeria monocytogenes presents a major challenge in the food industry. Routine monitoring is essential to ensure food safety in processing environments; therefore, rapid and reliable detection of Listeria is crucial for timely and effective intervention. OBJECTIVE: To validate the RapidChek® Listeria NextDay™ Plus test system for the detection of Listeria monocytogenes, Listeria innocua, Listeria seeligeri, Listeria welshimeri, Listeria ivanovii, Listeria marthii and Listeria grayi in selected foods including hot dogs, frozen cooked breaded chicken and vanilla ice cream, and on environmental surfaces, including stainless steel, plastic, rubber, and painted concrete using an unpaired study design. METHODS: The method uses a proprietary enrichment medium, a 24 to 48 h enrichment at 30 ± 1 °C and detects Listeria spp. on an immunochromatographic lateral flow device within 10 minutes. Listeria inoculated matrices were tested by the method, as well as the cultural reference method. The RapidChek method inclusivity was tested with 51 Listeria strains and its exclusivity using 30 non-target strains. RESULTS: Probability of detection (POD) analysis indicated no significant differences between the candidate method and the cultural reference method in the number of positive test portions detected for hot dogs, frozen cooked breaded chicken, stainless steel, plastic, and painted concrete. For vanilla ice cream and rubber, the candidate method yielded a greater number of positive test portions, with significantly higher POD values at the 95% confidence interval. Following enrichment, the RapidChek assay detected all 51 Listeria strains evaluated and produced no false positives among the 30 non-target organisms tested. CONCLUSIONS: The candidate method performed as well as the reference method in the detection of Listeria spp. on environmental surfaces after 24 h of enrichment and in selected food matrices after 27 h of enrichment. HIGHLIGHTS: Enriching for 24-27 h yielded reliable presumptive results for Listeria spp.