Title: Contamination of eggs by Salmonella Enteritidis in experimentally infected laying hens housed in conventional or enriched cages
Authors: Gast RK, Guraya R, Jones DR, Anderson K
Journal: Poult Sci
Accepted date: 2013 Nov 24
Interpretive summary: Internally contaminated eggs have been implicated in outbreaks of human illness caused by Salmonella Enteritidis more than any other food source. This pathogen is deposited inside eggs when infections of laying hens spread to the reproductive organs where eggs are formed. In recent years, considerable international attention has focused on the animal welfare and food safety consequences of different types of laying flock housing systems. In the present study, two different types of housing (conventional and enriched cages) were evaluated for their effects on egg contamination by laying hens infected with S. Enteritidis. Enriched cages are colony-type units providing greater floor space per bird with perches and enclosed nesting areas. After groups of laying hens were housed in each cage system and infected by oral inoculation, eggs were collected for several weeks and tested for S. Enteritidis contamination of their interior contents. No significant differences between the two housing systems were observed in the frequency of S. Enteritidis isolation from eggs. The public health consequences of housing systems for egg-laying flocks are related to both how long S. Enteritidis persists in the environment and how often infected hens lay contaminated eggs.