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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » ESQRU » Research » Publications at this Location » Publication #382400

Research Project: Evaluation of Management of Laying Hens and Housing Systems to Control Salmonella and Other Pathogenic Infections, Egg Contamination, and Product Quality

Location: ESQRU

Title: Contamination of eggs by Salmonella Enteritidis and Salmonella Typhimurium in experimentally infected laying hens in indoor cage-free housing

item Gast, Richard
item Jones, Deana
item Guraya, Rupinder - Rupa
item ANDERSON, KENNETH - North Carolina State University
item KARCHER, DARRIN - Purdue University

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/7/2021
Publication Date: 7/19/2021
Citation: Gast, R.K., Jones, D.R., Guraya, R., Anderson, K.E., Karcher, D.M. 2021. Contamination of eggs by Salmonella Enteritidis and Salmonella Typhimurium in experimentally infected laying hens in indoor cage-free housing. Poultry Science Association Meeting Abstract.

Interpretive Summary:

Technical Abstract: Contaminated eggs are a leading source of human Salmonella infections and this problem continues to challenge public health authorities and egg industries around the world. Salmonella invasion of the ovaries and oviducts of infected laying hens can result in bacterial deposition inside the edible portions of developing eggs. The introduction, persistence, and transmission of salmonellae in commercial egg-laying flocks are influenced by flock management practices, but the food safety ramifications of different types of laying hen housing remain unresolved. The present study assessed the frequency of internal contamination of eggs after experimental Salmonella Enteritidis and S. Typhimurium infection of laying hens in indoor cage-free housing. Groups of 72 hens were housed on wood shavings in isolation rooms simulating commercial cage-free barns with community kick-out nest boxes and perches and 1/3 of the hens in each room were orally inoculated with 8.0 × 10e7 cfu of 2-strain mixtures of either S. Enteritidis (2 rooms) or S. Typhimurium (2 rooms), and the entire internal contents of all eggs laid 5-30 d post-inoculation in nest boxes or on the flooring substrate were cultured to detect Salmonella. Contaminated eggs were laid between 8 and 28 d post-inoculation. The contamination frequencies associated with the two egg collection locations were not significantly different (P < 0.05 in Fisher’s exact test). The overall incidence of S. Enteritidis isolation from eggs (3.41%) was significantly (P = 0.0005) greater than S. Typhimurium (1.19%). These results demonstrate that oral infection of a relatively small proportion of laying hens in indoor cage-free housing with invasive Salmonella serovars can result in the production of internally contaminated eggs at low frequencies over a period of nearly a month post-inoculation.