title: A novel vehicle for transmission of Escherichia coli O157:H7 to humans: multistate outbreak of E. coli O157:H7 infections associated with consumption of ready-to-bake commercial prepackaged cookie dough--United States, 2009.
abstract: BACKGROUND
  Escherichia coli O157:H7 is a Shiga toxin-producing E. coli (STEC) associated with numerous foodborne outbreaks in the United States and is an important cause of bacterial gastrointestinal illness. In May 2009, we investigated a multistate outbreak of E. coli O157:H7 infections.
  
  
  METHODS
  Outbreak-associated cases were identified using serotyping and molecular subtyping procedures. Traceback investigation and product testing were performed. A matched case-control study was conducted to identify exposures associated with illness using age-, sex-, and state-matched controls.
  
  
  RESULTS
  Seventy-seven patients with illnesses during the period 16 March-8 July 2009 were identified from 30 states; 35 were hospitalized, 10 developed hemolytic-uremic syndrome, and none died. Sixty-six percent of patients were <19 years; 71% were female. In the case-control study, 33 of 35 case patients (94%) consumed ready-to-bake commercial prepackaged cookie dough, compared with 4 of 36 controls (11%) (matched odds ratio = 41.3; P < .001); no other reported exposures were significantly associated with illness. Among case patients consuming cookie dough, 94% reported brand A. Three nonoutbreak STEC strains were isolated from brand A cookie dough. The investigation led to a recall of 3.6 million packages of brand A cookie dough and a product reformulation.
  
  
  CONCLUSIONS
  This is the first reported STEC outbreak associated with consuming ready-to-bake commercial prepackaged cookie dough. Despite instructions to bake brand A cookie dough before eating, case patients consumed the product uncooked. Manufacturers should consider formulating ready-to-bake commercial prepackaged cookie dough to be as safe as a ready-to-eat product. More effective consumer education about the risks of eating unbaked cookie dough is needed.
authors.affiliation: Epidemic Intelligence Service, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. kneil@cdc.gov
authors.forename: Karen P
authors.initials: KP
authors.lastname: Neil
authors.forename: Gwen
authors.initials: G
authors.lastname: Biggerstaff
authors.forename: J Kathryn
authors.initials: JK
authors.lastname: MacDonald
authors.forename: Eija
authors.initials: E
authors.lastname: Trees
authors.forename: Carlota
authors.initials: C
authors.lastname: Medus
authors.forename: Kimberlee A
authors.initials: KA
authors.lastname: Musser
authors.forename: Steven G
authors.initials: SG
authors.lastname: Stroika
authors.forename: Don
authors.initials: D
authors.lastname: Zink
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sotir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D005260:Female; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D012703:Serotyping; D014481:United States / Q000453:epidemiology; D055815:Young Adult