fecal shedding in pigs from birth to market and its association with the presence of in palatine tonsils and submandibular lymph nodes at slaughter.

is an important cause of foodborne illnesses in humans. Food-producing animals, including swine, are a major source of in food products. This study investigated on farm fecal shedding in pigs at different production stages - from weaning to marketing - and its association with the presence of in tissues at slaughter. Fourteen groups from 8 commercial farrowing sources (N = 809 pigs) were monitored 5 times from birth to slaughter. Fecal and tissue samples were collected from pigs and cultured for A survey was conducted to collect farm management information. A multi-level mixed-effects logistic regression modelling method was used to analyze shedding over time and the association between shedding and the presence of in tissue samples. was recovered from 13% (421/3339) of fecal samples collected from 809 pigs over the course of the study. Overall, 35% (284) of pigs shed at least once, while 12% (99) shed more than once. shedding increased as pigs aged ( = 0.01) and increased in the summer months ( < 0.01). was isolated from tissue samples collected from 23% (134/580) of pigs; however, the presence of at slaughter was not associated with on farm shedding. The seasonal trend in shedding and its association with age may be used to identify high-risk groups and implement more effective control measures accordingly. The identification of repeat shedders warrants interventions that target this source of infection on swine farms.