title: Salmonella Typhimurium and Outbreaks of Egg-Associated Disease in Australia, 2001 to 2011.
abstract: Salmonellosis is a significant public health problem, with eggs frequently identified as a food vehicle during outbreak investigations. Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis are the two most frequently identified causes of egg-associated disease in industrialized countries. In Australia, a comprehensive review of egg-associated outbreaks has not been previously undertaken.
  
  
  
  Using a national register of foodborne outbreaks, we undertook a descriptive review of egg-associated outbreaks between 2001 and 2011. Included in our review was additional detail from the findings of trace back investigations conducted to the farm level. Evidence classifications were developed and applied to each outbreak based on descriptive and analytical epidemiology, food safety investigations, and microbiological testing of clinical, food, and trace back-derived samples.
  
  
  
  Over the study period, the proportion of foodborne Salmonella outbreaks linked to eggs increased significantly (p < 0.001). In total, 166 outbreaks were identified, with 90% caused by Salmonella Typhimurium. The majority of outbreaks were linked to commercial food providers, with raw egg use the major contributing factor. These events resulted in more than 3200 cases, more than 650 hospitalizations, and at least 4 deaths. Fifty-four percent of investigations used analytical epidemiology, food microbiology, and trace back microbiology to demonstrate links between human illness and eggs. Trace back investigations identified S. enterica indistinguishable from outbreak-associated clinical or food samples on 50% of sampled egg farms.
  
  
  
  Effective control of egg-associated salmonellosis remains a challenge in Australia, with Salmonella Typhimurium dominating as the causative serotype in outbreak events. Although outbreaks predominantly occur in the settings of restaurants, the high recovery rate of indistinguishable Salmonella on epidemiologically implicated egg farms suggests that further efforts to minimize infection pressure at the primary production level are needed in Australia.
authors.affiliation: 1 OzFoodNet, Communicable Disease Control, Health Protection Service, Australian Capital Territory Health Directorate , Canberra, Australia .|2 National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University , Canberra, Australia .
authors.forename: Cameron R M
authors.initials: CR
authors.lastname: Moffatt
authors.affiliation: 3 Health Protection New South Wales, New South Wales Ministry of Health , Sydney, Australia .
authors.forename: Jennie
authors.initials: J
authors.lastname: Musto
authors.affiliation: 4 OzFoodNet, Communicable Disease Control Directorate, Government of Western Australia , Department of Health, Perth, Australia .
authors.forename: Nevada
authors.initials: N
authors.lastname: Pingault
authors.affiliation: 5 OzFoodNet, Communicable Disease Control Branch, South Australia Health , Adelaide, Australia .
authors.forename: Megge
authors.initials: M
authors.lastname: Miller
authors.affiliation: 6 OzFoodNet, Communicable Diseases Branch , Queensland Health, Brisbane, Australia .
authors.forename: Russell
authors.initials: R
authors.lastname: Stafford
authors.affiliation: 7 OzFoodNet, Infectious Disease Epidemiology and Surveillance , Victorian Department of Health, Melbourne, Australia .
authors.forename: Joy
authors.initials: J
authors.lastname: Gregory
authors.affiliation: 8 OzFoodNet, Office of Health Protection , Australian Government Department of Health, Canberra, Australia .
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Polkinghorne
authors.affiliation: 2 National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University , Canberra, Australia .
authors.forename: Martyn D
authors.initials: MD
authors.lastname: Kirk
mesh_terms: D001315:Australia / Q000453:epidemiology; D004196:Disease Outbreaks; D004531:Eggs / Q000382:microbiology*; D005516:Food Microbiology; D006801:Humans; D011159:Population Surveillance; D012147:Restaurants; D012307:Risk Factors; D012478:Salmonella Food Poisoning / Q000453:epidemiology*; D012477:Salmonella enteritidis / Q000302:isolation & purification*; D012486:Salmonella typhimurium / Q000302:isolation & purification*