title: Three gastroenteritis outbreaks in South Korea caused by the consumption of kimchi tainted by norovirus GI.4.
abstract: BACKGROUND
  In April 2013, outbreaks of acute gastroenteritis were reported at three schools in Jeonju, South Korea. Epidemiological investigations were performed to characterize the outbreaks and implement appropriate control measures.
  
  
  METHODS
  Retrospective cohort studies were performed at these schools. Stool and environmental samples were collected for bacterial and viral assessment. A food supplier of the schools, food company X, was inspected, and samples of cabbage kimchi and groundwater were tested for norovirus by real-time reverse-transcriptase polymerase chain reaction. The relatedness of the detected norovirus strains was evaluated by phylogenetic analysis.
  
  
  RESULTS
  Of the 3347 questionnaires distributed, 631 (attack rate: 18.9%) met the case definition. Among the consumed food items, kimchi products (i.e., cabbage and fresh kimchi) were significantly associated with illness. The kimchi products were supplied by food company X. Among stool samples from 95 students and 34 food handlers at the 3 schools, 39 (41.1%) and 14 (41.2%) samples, respectively, were positive for norovirus. The samples of groundwater and cabbage kimchi at food company X were positive for norovirus. The predominant genotype of norovirus detected in the patient, groundwater, and cabbage kimchi samples, GI.4, shared high nucleotide identity.
  
  
  CONCLUSIONS
  Kimchi products tainted with norovirus GI.4 from contaminated groundwater were linked to the acute gastroenteritis outbreaks. Therefore, kimchi manufacturers in South Korea should apply chlorine disinfection when using groundwater. Moreover, more stringent sanitation requirements and strict regulations for food companies are recommended.
authors.affiliation: 1 Department of Preventive Medicine, Donngguk University College of Medicine , Gyeongju-si, Gyeongsangbuk-do, South Korea .
authors.forename: Ji-Hyuk
authors.initials: JH
authors.lastname: Park
authors.forename: Sunyoung
authors.initials: S
authors.lastname: Jung
authors.forename: Jaeseung
authors.initials: J
authors.lastname: Shin
authors.forename: Jeong Su
authors.initials: JS
authors.lastname: Lee
authors.forename: In Sun
authors.initials: IS
authors.lastname: Joo
authors.forename: Deog-Yong
authors.initials: DY
authors.lastname: Lee
mesh_terms: D004196:Disease Outbreaks; D005243:Feces / Q000821:virology*; D005506:Food Contamination; D005511:Food Handling; D005516:Food Microbiology; D005759:Gastroenteritis / Q000453:epidemiology*; D005838:Genotype; D006801:Humans; D029322:Norovirus / Q000302:isolation & purification*; D010802:Phylogeny; D012367:RNA, Viral / Q000302:isolation & purification; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012574:Schools; D011795:Surveys and Questionnaires
chemical_list: D012367:RNA, Viral