Contamination Pathways can Be Traced along the Poultry Processing Chain by Whole Genome Sequencing of .

Foodborne infection with causes potentially life-threatening disease listeriosis. is widely recognized as the only species of public health concern, and the closely related species is commonly used by the food industry as an indicator to identify environmental conditions that allow for presence, growth, and persistence of spp. in general. In our study, we analyze the occurrence of spp. in a farm-to-fork approach in a poultry production chain in Egypt and identify bacterial entry gates and transmission systems. Prevalence of at the three production stages (farm, slaughterhouse, food products) ranged from 11% to 28%. The pathogenic species was not detected, and strains under study did not show genetic virulence determinants. However, the close genetic relatedness of isolates (maximum 63 SNP differences) indicated cross-contamination between all stages from farm to final food product. Based on these results, chicken can be seen as a natural source of . Last but not least, sanitary measures during production should be reassessed to prevent bacterial contamination from entering the food chain and to consequently prevent human listeriosis infections. For this purpose, surveillance must not be restricted to pathogenic species.