title: Management and environmental risk factors for Salmonella enteritidis contamination of eggs.
abstract: OBJECTIVE
  To analyze data for 60 poultry flocks voluntarily enrolled in the Pennsylvania Salmonella enteritidis Pilot Project and determine management and environmental risk factors associated with production of S enteritidis-contaminated eggs.
  
  
  METHODS
  60 flocks for which at least 1 environmental sample (manure or egg-handling equipment) was positive for S enteritidis.
  
  
  METHODS
  Samples of manure, egg-handling equipment, and mice were submitted for bacterial culture of S enteritidis. When S enteritidis was isolated from environmental samples, 1,000 eggs were collected from the flock every 2 weeks for 8 weeks and submitted for bacterial culture.
  
  
  RESULTS
  18 flocks were found to have produced contaminated eggs. Estimated overall prevalence of contaminated eggs was 2.64/10,000 eggs produced, but flock-specific prevalence ranged from 0 to 62.5/10,000 eggs. Flocks with high levels of manure contamination were 10 times as likely to produce contaminated eggs as were flocks with low levels. However, 5 flocks with low levels of manure contamination produced contaminated eggs.
  
  
  CONCLUSIONS
  Evaluation of the level of manure contamination could be used to help identify flocks at risk of producing S enteritidis-contaminated eggs.
  
  
  CONCLUSIONS
  Flocks with high levels of S enteritidis-contaminated manure appeared to pose the greatest public health threat, and on-farm programs to reduce the prevalence of egg contamination should be developed for farms with high levels of manure contamination. Efforts to reduce the overall number of on-farm pathogens should decrease the incidence of foodborne disease in humans.
authors.affiliation: Food Safety and Inspection Service, USDA, Washington, DC 20250, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Henzler
authors.forename: D C
authors.initials: DC
authors.lastname: Kradel
authors.forename: W M
authors.initials: WM
authors.lastname: Sischo
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D002645:Chickens / Q000382:microbiology*; D004531:Eggs / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D051379:Mice; D010058:Oviposition; D010414:Pennsylvania; D010865:Pilot Projects; D012307:Risk Factors; D012477:Salmonella enteritidis / Q000302:isolation & purification*