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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Egg and Poultry Production Safety Research Unit » Research » Publications at this Location » Publication #412669
Research Project: Reducing Pathogen Contamination Risks and Improving Quality Attributes of Eggs and Egg Products through Housing System Management and Egg Handling Practices

Location: Egg and Poultry Production Safety Research Unit

Title: Environmental contamination and horizontal transmission of Salmonella Enteritidis among egg-type pullets in cage-free housing

Author
item Gast, Richard
item Garcia, Javier
item Jones, Deana
item Guraya, Rupinder
item KARCHER, DARRIN - Purdue University

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2024
Publication Date: 7/1/2024
Citation: Gast, R.K., Garcia, J.S., Jones, D.R., Guraya, R., Karcher, D. 2024. Environmental contamination and horizontal transmission of Salmonella Enteritidis among egg-type pullets in cage-free housing. Poultry Science Association (E. Suppl.):144 (Abstr).

Interpretive Summary:

Technical Abstract: The persistence and transmission of the egg-associated pathogen Salmonella Enteritidis in laying flocks are significantly influenced by the poultry housing environment. The egg industry is currently undergoing a transition toward increased utilization of cage-free housing systems, but the food safety implications of this shift are not yet fully understood. The present study assessed environmental contamination and horizontal transmission of S. Enteritidis within groups of layer pullets in cage-free housing after infection just before the age of sexual maturity. In each of 2 trials, 144 pullets were transferred from a rearing facility at 15 wk of age and randomly distributed between 2 isolation rooms simulating commercial cage-free barns with perches and nest boxes (72 birds/room). 24 pullets in each room were orally inoculated with S. Enteritidis at 1 wk after placement in the containment facility in trial 1 and 12 pullets in each room were similarly infected in trial 2. At 2 wk post-inoculation in each trial, samples of liver, spleen, and intestinal tract were collected from 40 uninoculated (contact-exposed) birds in each room for bacteriologic culturing to detect horizontal transmission of S. Enteritidis. At 6 intervals between inoculation and necropsy, 5 types of environmental samples (wall dust swab, nest box swab, perch swab, flooring substrate drag swab, and flooring substrate composite) were collected and cultured for S. Enteritidis. The overall frequency of S. Enteritidis recovery from internal organs of contact-exposed pullets after initial oral inoculation of 1/3 of the birds in each room (75.4%) was significantly greater (P < 0.0001 in Fisher’s Exact Test) than after initial infection of 1/6 of the birds (58.3%). The overall frequency of S. Enteritidis isolation from environmental samples was likewise significantly different between these 2 groups (98.3% vs. 87.1%, respectively; P < 0.0001). The frequency of recovery of S. Enteritidis from wall dust, the most efficient environmental sample for pathogen detection (95.8%), was significantly greater (P = 0.027) than from the least efficient sample (drag swabs; 79.2%). These data suggest that a high frequency of environmental contamination may be an important contributor to horizontal transmission of S. Enteritidis infections among pullets in cage-free housing.