Validation of Environmental Predictors of Salmonella Contamination in Feedlot Environments

<p>The foodborne pathogen Salmonella has been detected in peripheral lymph nodes (PLNs) of cattle at harvest (Arthur et al., 2008; Gragg et al., 2013a; Haneklaus et al., 2012). Fat trim containing lymph nodes may be a component of ground beef and has been identified as a potential source of Salmonella in this commodity. The mechanism of entry of Salmonella into bovine PLNs has yet to be determined, but it has been suggested that Salmonella present on cattle hides may be introduced through bites or wounds. Thus identifying effective tools for
assessing Salmonella levels in pre‐harvest environments is likely a key component to preventing infection of bovine tissues with this pathogen. Previous studies identified feedlot pen tank water and pen floor surface material as reliable sample types for the examination of Salmonella prevalence and levels in a given feedlot. Further, it was observed that aberrantly high levels of Salmonella contamination on cattle hides (defined as hides contaminated at ≥ 103 CFU/100cm2) was related to peripheral lymph node contamination with Salmonella. The research reported
here aimed to further examine the utility of these environmental samples for characterizing Salmonella levels on farm and for predicting the likelihood of downstream lymph node contamination.</p>