title: Yersinia pseudotuberculosis causing a large outbreak associated with carrots in Finland, 2006.
abstract: A large outbreak of Yersinia pseudotuberculosis O:1 infection affected over 400 children from 23 schools and 5 day-care centres in two municipalities in southern Finland in August-September, 2006. A retrospective cohort study conducted in a large school centre showed that the outbreak was strongly associated with the consumption of grated carrots served at a school lunch. The risk of illness increased with the amount of carrots eaten. Poor quality carrots grown the previous year had been delivered to the school kitchens in the two municipalities affected. In the patients' samples and in the environmental samples collected from the carrot distributor's storage facility, identical serotypes and genotypes of Y. pseudotuberculosis were found, but the original source and the mechanism of the contamination of the carrots remained unclear. Outbreaks of Y. pseudotuberculosis linked to fresh produce have been detected repeatedly in Finland. To prevent future outbreaks, instructions in improved hygiene practices on the handling of raw carrots have been issued to farmers, vegetable-processing plants and institutional kitchens.
authors.affiliation: Department of Infectious Disease Epidemiology, National Public Health Institute, Helsinki, Finland. ruska.rimhanen-finne@ktl.fi
authors.forename: R
authors.initials: R
authors.lastname: Rimhanen-Finne
authors.forename: T
authors.initials: T
authors.lastname: Niskanen
authors.forename: S
authors.initials: S
authors.lastname: Hallanvuo
authors.forename: P
authors.initials: P
authors.lastname: Makary
authors.forename: K
authors.initials: K
authors.lastname: Haukka
authors.forename: S
authors.initials: S
authors.lastname: Pajunen
authors.forename: A
authors.initials: A
authors.lastname: Siitonen
authors.forename: R
authors.initials: R
authors.lastname: Ristolainen
authors.forename: H
authors.initials: H
authors.lastname: Pöyry
authors.forename: J
authors.initials: J
authors.lastname: Ollgren
authors.forename: M
authors.initials: M
authors.lastname: Kuusi
mesh_terms: D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D002648:Child; D018552:Daucus carota / Q000382:microbiology*; D004196:Disease Outbreaks; D005260:Female; D005387:Finland / Q000453:epidemiology; D005506:Food Contamination; D005511:Food Handling; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015011:Yersinia pseudotuberculosis / Q000302:isolation & purification*; D015012:Yersinia pseudotuberculosis Infections / Q000453:epidemiology*