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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Egg Safety & Quality Research » Research » Publications at this Location » Publication #343314

Research Project: Reduction of Invasive Salmonella enterica in Poultry through Genomics, Phenomics and Field Investigations of Small Multi-Species Farm Environments

Location: Egg Safety & Quality Research

Title: IS THE DISTRIBUTION OF LISTERIA SPP. ISOLATED FROM ALL-NATURAL, MIXED SPECIES, PASTURED-RAISED BROILER FARMS RELATED TO DIFFERENTIAL GROWTH?

Author
item Locatelli, Aude - Oak Ridge Institute For Science And Education (ORISE)
item Rothrock, Michael

Submitted to: Federation of European Microbiological Societies Microbiology Letters
Publication Type: Abstract Only
Publication Acceptance Date: 3/16/2017
Publication Date: 7/9/2017
Citation: Locatelli, A., Rothrock Jr, M.J. 2017. IS THE DISTRIBUTION OF LISTERIA SPP. ISOLATED FROM ALL-NATURAL, MIXED SPECIES, PASTURED-RAISED BROILER FARMS RELATED TO DIFFERENTIAL GROWTH?. Federation of European Microbiological Societies Microbiology Letters. FEMS7-1359.

Interpretive Summary: Background: 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. Objectives: 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. Methods: 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, 30, 42°C). Conclusions: 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.

Technical Abstract: Background: 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. Objectives: 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. Methods: 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, 30, 42°C). Conclusions: 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.