E. coli O157:H7
Outbreak from Bagged Spinach
State health officials and CDC have identified
a widespread outbreak of E. coli O157:H7
infections due to bagged spinach in the United States.
The Food and Drug Administration (FDA) issued a press
release on September 14 advising consumers not to
eat bagged spinach. FDA and industry are
collaborating to remove produce that may be contaminated
from the market.
As of September 15, 94 persons infected with the
outbreak strain have been reported to CDC from 20
states. E. coli O157 causes a diarrheal
illness. Among the ill persons, 29 (31%) were hospitalized,
14 (15%) developed a type of kidney failure called
hemolytic-uremic syndrome (HUS), and an adult in
Wisconsin died.
Identification of the outbreak
E. coli O157 strains from all states are “fingerprinted” at
public health laboratories, as part of PulseNet (the
network of public health laboratories that sub-type
bacteria). The outbreak was first recognized in Wisconsin
when health officials received information about
an unusually high number of persons with recent E.
coli O157 infection. Around the same time, other
members of OutbreakNet (the network of public health
epidemiologists who investigate foodborne disease
outbreaks) were noticing smaller clusters of E.
coli O157 infections with the outbreak pattern.
OutbreakNet identified a multi-state outbreak on
September 13, and implicated bagged spinach the next
day.
The first reported illness associated with the outbreak
began on August 5, the most recently reported case
had onset of illness on September 5.
The states that have reported cases are WI (29), UT
(11), NY (7), OH (7), MI (6), NM (5), OR (5), IN
(4), ID (3), KY (3), PA (3), CT (2), ME (2), CA (1),
MN (1), NV (1), TN (1), VA (1), WA (1), and WY (1).
Spinach is the source
The data indicate that bagged spinach is the source.
Vegetables, including green leafy ones such as spinach,
are an important part of a healthy diet. The produce
industry already takes many precautions. However,
fresh produce can be contaminated in the field or
during processing. If it can be determined how contamination
occurred, additional measures can be designed to
prevent future illnesses.
Continuing investigation
State health officials are working to identify all
outbreak cases, and to determine the exact type(s)
and brand(s) of spinach they consumed. CDC is coordinating
the multi-state aspects of the investigation. FDA
and industry are collaborating with state health
officials and CDC to quickly gather information and
take actions to protect the public.
Advice
for consumers about this outbreak
The following
is advice for consumers about this outbreak:
- FDA has advised
consumers not to eat bagged spinach at this time.
- Persons who develop a
diarrheal illness and who ate bagged spinach in the
previous week should contact their health-care provider
and have a stool specimen tested for E. coli O157.
- Persons who ate bagged
spinach and feel well do not need to see a health-care
provider
General information about E. coli O157
infection
E. coli O157 bacteria cause diarrhea that
is often bloody. The diarrhea is often accompanied
by abdominal cramps, but fever is absent or mild.
Illness typically resolves within a week. However,
some people, especially children under 5 years old
and the elderly, develop a type of kidney failure
called hemolytic-uremic syndrome (HUS). Among children
with HUS, 5% die.
General information about timing of reporting
After a person ingests contaminated food, 3-4 days
typically pass before illness begins. Then a few
days often pass before the person seeks medical care
and submits a stool specimen. The laboratory spends
a few days culturing the stool and identifying the
causative agent as E. coli O157. The laboratory
then sends the strains to the state public health
laboratory. This laboratory spends a few days sub-typing
the E. coli O157 according to the PulseNet
subtyping protocol. They then download the “fingerprint” pattern
into a CDC database. Laboratorians and epidemiologists
in states and at CDC review this information daily
to detect clusters of similar strains that could
represent outbreaks due to a common source. The epidemiologists
then call the ill persons to ask about their recent
exposures. If everything goes quickly, a person could
be interviewed within 2 weeks after eating a contaminated
food, but delays can occur at any point.
In addition, in most outbreaks, the number of reported
ill persons is usually the “tip of the iceberg.” Other
persons have probably developed illness due to this
same strain, but did not have a culture to confirm
the cause, either because a stool specimen was not
tested, or the clinical laboratory did not perform
the specific test for E. coli O157.
General advice for consumers about E.
coli O157 in produce
The following is advice for consumers about protecting
themselves from infection with E. coli O157
in produce:
E. coli O157 is highly susceptible
to heat. For example, E. coli strains in
water are killed after 1 minute of boiling. Cooking
vegetables well will kill E. coli. Ideally,
food that will be consumed without cooking should
be safe to eat. However, bacteria stick to produce
even when it is washed, and sometimes the bacteria
are inside the produce. These are some things consumers
can do to protect themselves from bacteria in produce
consumed without cooking:
- Wash produce with clean
cool running water just before eating and cut away
damaged areas. (Firm produce can also be scrubbed
with a brush.)
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- Peel fruits and remove
the outer leaves of leafy vegetables.
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- Wash hands before handling
food and in between handling different types of food
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- Avoid cross-contamination – use
a different knife and cutting board for meat and produce.
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- Avoid drinking unpasteurized
juice.
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Supermarkets and restaurants can require their suppliers
to provide proof that produce is handled using the
best hygienic practices all the way from the farm
to the table.
Source
Centers for Disease Control and Prevention
http://www.cdc.gov/
More Information...
Escherichia coli O157:H7
E. coli O157:H7 Outbreak from Bagged Spinach Update on Multi-State Outbreak of E. coli O157:H7
Infections From Bagged Spinach, September
15, 2006
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