Occurrence and detection of Listeria monocytogenes in ready-to-eat foods

Abstract Listeria monocytogenes is a pathogenic bacterium that causes listeriosis. Listeriosis is a serious and often fatal disease caused by the ingestion of contaminated foods. Listeria monocytogenes contaminates various types of food. It turns out that ready-to-eat foods can be a very common source of this pathogenic bacteria. The aim of this study was to evaluate the microbial quality of ready-to-eat foods. The main focus was given on evaluation of the presence of L. monocytogenes in this group of food. Total number of 50 samples were devided into three categories: pastries (n = 29), salads (n = 13) and others (n = 8). All samples were analyzed for presence of L. monocytogenes using a conventional cultivation method ISO 11290-1:2017. As confirmation tests were used API Listeria test and PCR. The presence of L. monocytogenes was detected in 3 (1.5%) samples. All positively tested samples belonged to the category pastries, specifically: Caesar wrap, Caprese mozzarella and dried tomatoes tortilla, Halloumi cheese and roasted pepper tortilla. The results of this study indicate that consumption of RTE foods can pose a risk of listeriosis, especially for consumers from susceptible risk groups.