An outbreak of Escherichia coli O157:H7 infection from unpasteurized commercial apple juice.
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.


METHODS
Descriptive epidemiologic study and traceback investigation.


METHODS
Western United States and British Columbia, Canada.


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


METHODS
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.
Cody
S H
SH
California Department of Health Services, Berkeley 94704, USA.
Glynn
M K
MK
Farrar
J A
JA
Cairns
K L
KL
Griffin
P M
PM
Kobayashi
J
J
Fyfe
M
M
Hoffman
R
R
King
A S
AS
Lewis
J H
JH
Swaminathan
B
B
Bryant
R G
RG
Vugia
D J
DJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D001628:Beverages / Q000009:adverse effects / Q000382:microbiology*; D001955:British Columbia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000209:etiology; D019453:Escherichia coli O157; D005638:Fruit / Q000009:adverse effects / Q000382:microbiology*; D006463:Hemolytic-Uremic Syndrome / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007223:Infant; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013242:Sterilization; D014481:United States / Q000453:epidemiology