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An Outbreak of Escherichia coli O157:H7 Infection from Unpasteurized Commercial Apple Juice

Sara H. Cody, MD; M. Kathleen Glynn, DVM, MPVM; Jeff A. Farrar, DVM, MPH, PhD; K. Lisa Cairns, MD, MPH; Patricia M. Griffin, MD; John Kobayashi, MD; Murray Fyfe, MD, MSc, FRCPC; Richard Hoffman, MD, MPH; Arlene S. King, MD, FRCPC; Jay H. Lewis, BS; Balasubr Swaminathan, PhD; Raymond G. Bryant, BA; and Duc J. Vugia, MD, MPH
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From California Department of Health Services, Berkeley, Sacramento, California; Centers for Disease Control and Prevention, Atlanta, Georgia; Washington State Department of Health, Shoreline, Washington; British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada; Laboratory Centre for Disease Control, Health Canada, Ottawa, Ontario, Canada; and Colorado Department of Public Health and Environment, Denver, Colorado.

Ann Intern Med. 1999;130(3):202-209. doi:10.7326/0003-4819-130-3-199902020-00005
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Background: Escherichia coli O157:H7 infections have traditionally been associated with animal products, but outbreaks associated with produce have been reported with increasing frequency. In fall 1996, a small cluster of E. coli O157:H7 infections was epidemiologically linked to a particular brand (brand A) of unpasteurized apple juice.

Objective: To define the extent of the outbreak, confirm the source, and determine how the apple juice became contaminated.

Design: Descriptive epidemiologic study and traceback investigation.

Setting: Western United States and British Columbia, Canada.

Patients: Patients with E. coli O157:H7 infection who were exposed to brand A apple juice.

Measurements: Clinical outcome and juice exposure histories of case-patients, pulsed-field gel electrophoresis of case and juice isolates, and juice production practices.

Results: Seventy persons with E. coli O157:H7 infection and exposure to brand A unpasteurized apple juice were identified. Of these persons, 25 (36%) were hospitalized, 14 (20%) developed the hemolytic uremic syndrome, and 1 (1%) died. Recalled apple juice that was produced on 7 October 1996 grew E. coli O157:H7 with a pulsed-field gel electrophoresis pattern indistinguishable from that of case isolates. Apple juice produced on 7 October 1996 accounted for almost all of the cases, and the source of contamination was suspected to be incoming apples. Three lots of apples could explain contamination of the juice: Two lots originated from an orchard frequented by deer that were subsequently shown to carry E. coli O157:H7, and one lot contained decayed apples that had been waxed.

Conclusions: Standard procedures at a state-of-the-art plant that produced unpasteurized juices were inadequate to eliminate contamination with E. coli O157:H7. This outbreak demonstrated that unpasteurized juices must be considered a potentially hazardous food and led to widespread changes in the fresh juice industry.


Grahic Jump Location
Figure 1.
Outbreak-associated cases ofEscherichia coliO157:H7 by date of diarrhea onset (n= 70) for British Columbia, California, Colorado, and Washington (fall 1996).

Each box represents one outbreak-associated case.

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Figure 2.
Dates of consumption of brand A apple juice for case-patients exposed to only one juice on one date (n= 31) for British Columbia, California, Colorado, and Washington (fall 1996).

Apple juice and blended juices containing apple juice that were produced on 7 October 1996 could have been consumed at any time during their 17-day shelf life or after the expiration date. At least 2 days usually elapse between production of juice and retail sale.

Grahic Jump Location




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