Environmental sampling methods' influence on detection of pathogens in cage-free aviary housing

Authors: Garcia, Javier; Jones, Deana; Gast, Richard; KARCHER, DARRIN - Purdue University; ERASMUS, MARISA - Purdue University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2022
Publication Date: 2/1/2023
Citation: Garcia, J.S., Jones, D.R., Gast, R.K., Karcher, D., Erasmus, M.A. 2023. Environmental sampling methods' influence on detection of pathogens in cage-free aviary housing. Poultry Science. https://doi.org/10.1016/j.psj.2022.102381.
DOI: https://doi.org/10.1016/j.psj.2022.102381

Interpretive Summary: Environmental sampling can be a important tool to determine the status of a layer housing system in regards to pathogens of human health concern. To identify the natural occurrence of pathogens (Listeria, Campylobacter and Salmonella) at various locations within a cage-free aviary housing system, swabs samples were collected when the hens were 22 - 39 weeks of age. Duplicate swab samples were also taken and inoculated with a low dose of Salmonella Enteritidis to determine the recovery of Salmonella Enteritidis from environmental samples. Detection of Listeria was the highest at the beginning of the study (22 weeks) and decreased over time. Campylobacter was also the highest at the beginning of the study but decreased at a more gradual rate than Listeria. The detection of Campylobacter in concrete dust samples could be associated to the presence of rodent feces. Drag swabs and manure belt scraper swabs had the highest detection of Listeria and Campylobacter. No naturally occurring Salmonella was detected in any of the environmental samples. The recovery of Salmonella Enteritidis from inoculated environmental samples increased over time and was at the highest by 39 weeks. Based on this study, the use of drag and manure belt scraper swabs are effective in detecting Listeria and Campylobacter in cage-free aviary housing. Along with good pest management, the occurrence of pathogens could be monitored and reduced in laying hen flocks.

Technical Abstract: The environmental sampling of layer housing systems is essential to identifying potential pathogens that are of concern to human health. To identify the natural occurrence of pathogens (Listeria, Campylobacter and Salmonella) at various locations in a cage-free aviary housing system, swabs were collected when hens were 22 - 39 wks of age. Duplicate swabs were inoculated with a low dose (101 cfu) Salmonella Enteritidis (SE) and examined for the recovery of SE from environmental samples. Detection of Listeria (P < 0.0001) and Campylobacter (P < 0.0001) varied between the environmental sample types taken: concrete dust, drag swabs, egg belt dust, manure belt scraper swabs, and wall dust. Detection of Listeria (P < 0.0001) was the highest (70.0 %) at the beginning of the study (22 wk) and decreased over time. Detection of Campylobacter (P < 0.001) was also the highest at 22 wk, however the decrease over time was more gradual. Interestingly, detection of Campylobacter (P < 0.0001) was the greatest in concrete dust samples (96.25 %), which can be attributed to the presence of rodent excreta in the samples. Drag swabs and manure belt scraper swabs were the best sampling types for high detection of Listeria and Campylobacter. No naturally occurring Salmonella was identified in this study. The recovery of the SE inoculum increased over time, reaching the greatest recovery in drag (81.25 %; P < 0.0001), egg belt dust (100.00 %; P < 0.0001) and wall dust swabs (100.00 %; P < 0.0001) by 39 wk. This high rate of SE recovery occurred just before US mandatory SE environmental monitoring at 40 – 45 wks of age. Based on this study, the use of drag and manure belt scraper swabs are effective in detecting Listeria and Campylobacter in cage-free aviary housing. Along with good pest management, the occurrence of pathogens could be monitored and reduced in laying hen flocks.