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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » ESQRU » Research » Publications at this Location » Publication #384504

Research Project: Reducing Pathogen Contamination Risks and Improving Quality Attributes of Eggs and Egg Products through Housing System Management and Egg Handling Practices

Location: ESQRU

Title: Tissue colonization and egg and environmental contamination associated with experimental infection of laying hens with Salmonella Braenderup

Author
item Garcia, Javier
item Gast, Richard
item Jones, Deana

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/7/2021
Publication Date: 7/19/2021
Citation: Garcia, J.S., Gast, R.K., Jones, D.R. 2021. Tissue colonization and egg and environmental contamination associated with experimental infection of laying hens with Salmonella Braenderup. Poultry Science Association Meeting Abstract. Poultry Science. 100(1):238.

Interpretive Summary: Salmonella Enteritidis is a foodborne pathogen of concern to the egg industry. However, other strains of Salmonella, such as Salmonella Braenderup, can cause foodborne illness in humans and has been linked to outbreaks associated with shell eggs. The focus of this study was to examine the impact of Salmonella Braenderup on organ invasion, egg and environmental contamination. Cage-free laying hens were infected with Salmonella Braenderup. On day 6 post-inoculation, half of the infected flocks (36 hens/trial) were euthanized and tissue samples were collected. On day 7 to day 20 post-inoculation (excluding weekends; 10 days total egg collection/trial) and day 7 to day 27 post-inoculation (excluding weekends; 15 days total egg collection/trial) in trials 3 and 4. Nest box swabs and substrate composite samples were also collected at the time of daily egg collection. Invasion of internal organs and egg contamination was found to be very low compared to other strains of Salmonella. Environmental contamination varied throughout the trials and further research is needed to investigate how Salmonella Braenderup in the environmental could lead to internal and/or external egg contamination.

Technical Abstract: Salmonella is a major foodborne pathogen of concern with the focus on Salmonella Enteritidis for the egg industry. In recent years, other serovars of Salmonella, such as Salmonella Braenderup, have been linked to foodborne illness outbreaks associated with shell eggs. However, little is known of Salmonella Braenderup infections in laying hens. The objective of this study was to investigate the influence of Salmonella Braenderup on organ invasion, as well as egg and environmental contamination. Cage-free specific-pathogen-free laying hens (Trial 1 and 2, 43 – 45 weeks old; Trial 3 and 4, 54 – 56 weeks old; 72 hen/trial) were orally challenged with 7 log cfu of the egg-associated human outbreak isolate of Salmonella Braenderup (SB). On day 6 post-inoculation, half of the challenged flocks (36 hens/trial) were euthanized and tissue samples (ileocecal junction, liver, spleen, ovary, and oviduct) were collected. In trials 1 and 2, eggs were collected from day 7 to day 20 post-inoculation (excluding weekends; 10 days total egg collection/trial) and day 7 to day 27 post-inoculation (excluding weekends; 15 days total egg collection/trial) in trials 3 and 4. Nest box swabs and substate composite samples were also collected at the time of daily egg collection. Recovery of SB for all samples was analyzed by Chi-square. The rate of SB recovery from organ tissue samples varied between the four trials. In trial 2, 33.3% (P < 0.05) of the ileocecal samples were positive for SB, the highest recovery rate of all the trials. Rate of SB recovery from the other organ tissues samples was between 0 and 5.6%. Recovery of SB from egg and environmental samples also varied between the trials. In trial 2, SB was detected in 2.9% of shell emulsions (P < 0.0043) compared to the other trials with no detected SB. Salmonella Braenderup was only detected in nest box swabs in trial 2 (7.5%; P < 0.02). In trial 1, SB was detected in 92.5% (P < 0.0001) of substrate composite samples compared to the other trials (2.5 – 17.5%). In the current study, Salmonella Braenderup was found to invade the organs of laying hens and contaminate eggs at a low rate. Further research is needed to determine how the presence of Salmonella Braenderup in the environment could contaminate shell eggs internally and externally .