Purpose: The purpose of this study was to conduct a comparative study between the 3M Molecular Detection System (MDS) and Traditional Method, supported by Polymerase Chain Reaction (PCR) to determine the sensitivity, specificity, false positive and false negative rates.
Methods: Eighty naturally contaminated seafood samples - (n=40) sushi and (n=40) sashimi - were analyzed, according to the 3M MDA L. monocytogenes protocol (enrichment lysis, amplification and detection) and the Food and Drug Administration (FDA) protocol (enrichment, isolation in selective solid and differential agar media, and confirmation by biochemical tests). PCR was used to confirm the genus for colonies obtained by standard methodology.
Results: 3M MDA L. monocytogenes detected ten positive samples out of the eighty naturally contaminated samples (5 sushi, 5 sashimi). Presumptive positives were confirmed by the conventional method using biochemical tests. The methods showed sensitivity and specificity of 100% and 0% rates of false positives and false negatives when compared to the FDA methodology.
Significance: Sushi and Sashimi are very popular in Brazil and due to the Olympic games that will happen in 2016, thousands of foreign visitors will arrive in the country. It is crucial to detect critical risk products and apply control measures to achieve food safety in ready to eat food. In this study, it was observed that 12.5% of the samples tested were positive for this important pathogen. The use of a rapid, sensitive and specific method for the detection of L. monocytogenes can promote public health, supporting regulatory agencies in controlling the consumption of potentially contaminated food with lower time to results and the same reliability as standard methods.