Location: Egg Safety & Quality ResearchTitle: Does differential growth affect the distribution and recovery of Listeria spp. in pasture-raised broiler farm soils? Author
|Locatelli, Aude - Department Of Energy|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2017
Publication Date: 7/16/2017
Citation: Locatelli, A., Rothrock Jr, M.J. 2017. Does differential growth affect the distribution and recovery of Listeria spp. in pasture-raised broiler farm soils?. Poultry Science Association Meeting Abstract. p 542.
Technical Abstract: Listeria spp. represent an important foodborne pathogen, but relatively little is known about its environmental prevalence on poultry farms. Considering the environmental exposure inherent with pasture-raised production systems, these types of alternative poultry management systems represent an ideal setting to determine environmental Listeria spp. diversity and prevalence. Initial surveys of the isolate datasets revealed that across the farms samples L. innocua (59%) was found predominantly in feces and soil samples followed by L. monocytogenes (33%) and L. welshimeri (2%). Based on theses observations, we wanted to evaluate whether the distribution of Listeria species evidenced in broiler farms could results from a differential growth in liquid media. Four Listeria strains isolated from soil were selected including one of each L. monocytogenes serogroups and one of L. innocua. These strains were inoculated either separately or in mixed culture in Tripticase Soy Broth (TSB) and University of Vermont (UVM) modified Listeria enrichment broth at 102 and 105 cells per ml and incubated for 24-48 hrs at 3 temperatures (20°C, 30°C, 42°C). Overall, the inoculum concentration and the liquid media have a significant effect on Listeria growth at all temperatures. No significant differences were observed between the growths of the three L. monocytogenes strains. In UVM media, a significantly shorter lag phase was observed for L. innocua compared to L. monocytogenes strains for both inoculum concentrations. This difference in the growth dynamic between may help to explain the Listeria species recovered from these broiler farms.