Batista,RitaChambel,Lélia Mariana MarcãoCoelho, Ana Carolina Dias2026-05-192026-05-192025http://hdl.handle.net/10400.5/118628Tese de Mestrado, Biologia Humana e Ambiente, 2025, Universidade de Lisboa, Faculdade de CiênciasThe current lifestyle, characterized by increasingly hectic routines, influences the population’s eating habits, leading to a preference for quick-to-prepare and easy-to-cook foods. Among these, meat preparations such as hamburgers, and ready-to-eat meat products, have seen a growing consumption trend. However, as these foods are often consumed raw or undercooked, they may pose a public health risk if contaminated with pathogenic bacteria. This study aimed to analyze the presence of Salmonella spp. as well as the presence and enumeration of Listeria monocytogenes, in meat products purchased in retail stores in Lisbon, Portugal, such as 75 meat preparations (hamburgers) and 75 sliced ready-to-eat charcuterie products. In total, 150 samples were analyzed using methods based on ISO standards and the automated VIDAS® and VITEK®2 systems. The isolates obtained were characterized through Whole Genome Sequencing (WGS) and compared with clinical isolates from the National Institute of Health Doctor Ricardo Jorge (INSA) database. In the charcuterie products, Salmonella spp. was not detected, and only two samples (2.7%) tested positive for Listeria monocytogenes. In meat preparations, the prevalence was 8% for Salmonella spp. and 73.33% for Listeria monocytogenes. Genomic analysis allowed the identification of one Salmonella spp. cluster and ten Listeria monocytogenes clusters, as well as a high genetic proximity of four Salmonella spp. strains and twenty-two Listeria monocytogenes strains with clinical human isolates. These results suggest failures along the production chain and highlight the importance of strict microbiological control, revision of legislation applicable to meat and meat products, and continuous training of food sector professionals.application/pdfporSalmonella spp.Listeria monocytogenesMeat preparationsReady-to-eat sliced meat and meat productsFoodborne pathogensmaster thesis