Purpose: This study aimed to evaluate the 3M Molecular Detection Assay 2 Listeria (3M MDA 2 Listeria) compared to the conventional ISO 11290-1 method.
Methods: A total of 109 chicken meat samples and 110 environmental samples were screened in duplicate for Listeria using ISO 11290-1 culture method and 3M MDA 2 Listeria. Listeria innocua and Listeria ivanovii (at 200, 20, 2, 0.2, 0.02, and 0.002 CFU per unit) were used to artificially inoculate samples (n = 49 chicken meat and n = 50 environmental samples) to determine accuracy, sensitivity, and specificity. PCR targeting prsA gene and sequencing were performed on presumptive colonies to confirm the genus.
Results: Of the naturally contaminated chicken meat (n = 60) and environmental (n = 60) samples, 21 and 20 samples were positive for Listeria by the conventional method and the 3M MDA 2 Listeria, respectively. The 3M MDA 2 detected Listeria species with 92.66% relative accuracy, 93.65% relative specificity, and 91.30% relative sensitivity from 109 chicken meat samples, naturally and artificially contaminated. From 110 environmental samples the percentages for relative accuracy, specificity, and sensitivity were 91.82, 91.04, and 93.02, respectively. The detection limit for Listeria spp. was < 2 CFU per unit.
Significance: This study demonstrated that for the 3M MDA 2 Listeria detection of this microorganism is reliable and accurate compared to ISO 11290-1. This rapid molecular technique offers a faster response time to control contamination in the food production chain.