Distribution of Listeria monocytogenes serotypes in meat and meat products and risk assesment for food safety

Listeria monocytogenes is a foodborne pathogen that can cause serious diseases in humans and has a high mortality rate. Contamination with L. monocytogenes, particularly during the processing, transport, and storage of meat and meat products, poses a risk to public health. The aim of this study was to determine the presence of L. monocytogenes in red meat and meat products, identify the serotypes that may be pathogenic, and assess the risk of infection from consumed foods in terms of public health. The study analysed samples of raw and processed meat products, including minced meat, sausage, salami, and sausage, taken from retail outlets in Istanbul under aseptic conditions. The results of cultural methods and biochemical tests identified a total of 83 suspected isolates of Listeria spp., with 24 (8%) identified as L. monocytogenes. Confirmation of L. monocytogenes isolates was carried out using the Vitek 2 system. Of the total isolates, 24 (28.9%) were identified as L. monocytogenes, 44 (53%) as L. innocua, 5 (6%) as L. grayi, 6 (7.2%) as L. welshimeri, and 4 (4.8%) as Listeria spp. The distribution of L. monocytogenes isolates according to serotypes was as follows: 10 (41.6%) 1/2a, 3 (12.5%) 1/2b, 1 (4.8%) 1/2c, 5 (20.8%) 3a, 4 (19%) 3c, and 1 (4.8%) 4b serotypes. The quantitative risk assessment revealed that 98 minced meat and meat products, 7 sausage products, 1 salami, and 1 sausage product of 0.3 kg per day could be contaminated with L. monocytogenes. It is important to note that this assessment is based on objective data and does not include any subjective evaluations. It is predicted that cross-contamination plays an important role in L. monocytogenes contamination. Therefore, it is crucial to implement effective food safety management approaches and measures at all stages of the consumer level, including slaughter, processing, retail, transport, and cooking of red meat and meat products. This will help to reduce the burden of exposure to this risk.