title: Partial Failure of Milk Pasteurization as a Risk for the Transmission of Campylobacter From Cattle to Humans.
abstract: BACKGROUND
  Cattle are the second most common source of human campylobacteriosis. However, routes to account for this scale of transmission have not been identified. In contrast to chicken, red meat is not heavily contaminated at point of sale. Although effective pasteurization prevents milk-borne infection, apparently sporadic infections may include undetected outbreaks from raw or perhaps incompletely pasteurized milk.
  
  
  METHODS
  A rise in Campylobacter gastroenteritis in an isolated population was investigated using whole-genome sequencing (WGS), an epidemiological study, and environmental investigations.
  
  
  RESULTS
  A single strain was identified in 20 cases, clearly distinguishable from other local strains and a reference population by WGS. A case-case analysis showed association of infection with the outbreak strain and milk from a single dairy (odds ratio, 8; Fisher exact test P value = .023). Despite temperature records indicating effective pasteurization, mechanical faults likely to lead to incomplete pasteurization of part of the milk were identified by further testing and examination of internal components of dairy equipment.
  
  
  CONCLUSIONS
  Here, milk distribution concentrated on a small area, including school-aged children with low background incidence of campylobacteriosis, facilitated outbreak identification. Low-level contamination of widely distributed milk would not produce as detectable an outbreak signal. Such hidden outbreaks may contribute to the substantial burden of apparently sporadic Campylobacter from cattle where transmission routes are not certain. The effective discrimination of outbreak isolates from a reference population using WGS shows that integrating these data and approaches into surveillance could support the detection as well as investigation of such outbreaks.
authors.affiliation: Operations Directorate.
authors.forename: Anand M
authors.initials: AM
authors.lastname: Fernandes
authors.affiliation: Field Epidemiology Services.
authors.forename: Sooria
authors.initials: S
authors.lastname: Balasegaram
authors.affiliation: Food, Water and Environment Laboratory, Public Health England.
authors.forename: Caroline
authors.initials: C
authors.lastname: Willis
authors.affiliation: Department of Zoology.
authors.forename: Helen M L
authors.initials: HM
authors.lastname: Wimalarathna
authors.affiliation: Department of Zoology National Institute for Health Research Health Protection Research Unit in Gastrointestinal Infections, University of Oxford.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Maiden
authors.affiliation: Field Epidemiology Services Department of Zoology National Institute for Health Research Health Protection Research Unit in Gastrointestinal Infections, University of Oxford Warwick Medical School, University of Warwick, United Kingdom.
authors.forename: Noel D
authors.initials: ND
authors.lastname: McCarthy
mesh_terms: D000328:Adult; D000818:Animals; D002167:Campylobacter / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002169:Campylobacter Infections / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D062665:Epidemiological Monitoring; D005260:Female; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000209:etiology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D008892:Milk / Q000382:microbiology*; D058889:Molecular Typing; D061352:Pasteurization; D018570:Risk Assessment; D017422:Sequence Analysis, DNA; D055815:Young Adult; D015047:Zoonoses / Q000175:diagnosis / Q000382:microbiology / Q000635:transmission*
keywords: Campylobacter; cattle; milk; pasteurization; whole-genome sequencing