in eggs and egg-laying chickens: pathways to effective control.

Abstract

Eggs contaminated withhave been internationally significant sources of human illness for several decades. Most egg-associated illness has been attributed toserovar Enteritidis, but a few other serovars (notablyHeidelberg andTyphimurium) are also sometimes implicated. The edible interior contents of eggs typically become contaminated withEnteritidis because the pathogen's unique virulence attributes enable it to colonize reproductive tissues in systemically infected laying hens. Other serovars are more commonly associated with surface contamination of eggshells. Both research and field experience have demonstrated that the most effective overallcontrol strategy in commercial laying flocks is the application of multiple interventions throughout the egg production cycle. At the preharvest (egg production) level, intervention options of demonstrated efficacy include vaccination and gastrointestinal colonization controltreatments such as prebiotics, probiotics, and bacteriophages, Effective environmental management of housing systems used for commercial laying flocks is also essential for minimizing opportunities for the introduction, transmission, and persistence ofin laying flocks. At the postharvest (egg processing and handling) level, careful regulation of egg storage temperatures is critical for limitingmultiplication inside the interior contents.