- Hello Jeff - In short, no one has a clue as to how the
cantaloupes became infected. If they do know, they may not wish to say.
Use of treated sewage...otherwise known as 'reclaimed water' for irrigation
comes to mind.
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- The authorities are just hoping it will all blow over
in the press, as usually happens. Del Monte got away with infected cantaloupes
this February 2011. That outbreak was barely noticed, except for the family
of the person who died and the 20 individuals who took ill across 10 States.
They all noticed!
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- The article below simply looks like guess work is the
norm.
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- Patty
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- Sheep Among Many Sources In Farm Listeria Probe
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- By Lisa Schnirring
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- CIDRAP Staff Writer
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- (CIDRAP News) -- Investigators working to discover how
Jensen Farms' cantaloupe became contaminated with Listeria monocytogenes,
leading to the country's deadliest foodborne illness outbreak in almost
a decade, are taking a hard look at several environmental factors, including
whether sheep grazing in the region may have played a role.
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- Dr Lawrence Goodridge, a food microbiologist in the department
of animal sciences at Colorado State University in Fort Collins, was involved
in the outbreak investigation as an expert consultant during its early
stages and is part of a team focusing on several research questions the
events have raised.
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- So far federal investigators have detected Listeria on
Jensen Farms cantaloupe collected from Denver-area grocery stores and from
equipment and cantaloupe at the farm's packing facility in Granada, Colo.,
according to a Sep 19 US Food and Drug Administration (FDA) statement.
Colorado officials have confirmed that cantaloupe from a sick patient's
home and from retail outlets match the outbreak strain's genetic fingerprint.
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- According to an update yesterday from the US Centers
for Disease Control and Prevention (CDC), the outbreak has been linked
to 100 infections and 18 deaths in 20 states. Last week CDC officials called
it the deadliest foodborne outbreak in nearly a decade.
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- All potential sources of contamination are being considered,
including irrigation water, soil, "biosolids," and contamination
from animal incursions, Goodridge said. Biosolids are processed residual
material from sewage treatment that is used as fertilizer on farms. He
said biosolids were spread on a field adjacent to Jensen Farms 2 years
ago.
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- Though investigators haven't mentioned focusing on a
suspected animal vector, Goodridge said one possibility is sheep. In the
region of Colorado where cantaloupes are grown-though not necessarily at
the farm implicated in the outbreak-sheep are often grazed on cantaloupe
fields following harvest, he said.
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- "If that practice was followed at Jensen Farms,
then there is the possibility of sheep manure contaminating the cantaloupe
with L monocytogenes," he said. A similar scenario occurred in Nova
Scotia, Canada, in 1981 when a Listeria outbreak caused by tainted cabbage
was traced to the use of sheep manure as fertilizer, Goodridge added.
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- The Canadian Listeria outbreak sickened seven adults
and led to 34 perinatal infections, according to a report on the outbreak
published in 1983 in the New England Journal of Medicine (NEJM). After
two case-control studies found no common environmental or food exposure
among the sick patients, a second food survey found a link to eating coleslaw.
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- A coleslaw sample from a patient's refrigerator was positive
for the outbbreak strain of Listeria, called serotype 4b. The product trace-back
revealed that a regional firm made the coleslaw with cabbage and carrots
from several wholesalers and local farmers and distributed the product
only in Canada's Maritime Provinces.
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- Environmental tests at the coleslaw plant found no Listeria
contamination, but after prolonged cold enrichment, two unopened packages
purchased at two Halifax grocery stores tested positive for Listeria serotype
4b. The produce-trace back led to a farm where both cabbage and sheep were
raised. According to the NEJM report, two of the farm's sheep had died
from listeriosis, though isolates from the animals weren't available for
serotyping.
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- The farmer had used composted and raw manure from the
sheep flock to fertilize the cabbage crops. The coleslaw plant had received
a shipment of cabbage that had been kept in the farm's cold-storage shed
over the winter. None of the stored cabbage was available for testing,
and environmental samples from the farm never yielded Listeria, according
to the report.
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- Canadian investigators wrote that the farming practices
provided ample opportunity for introducing Listeria into the food chain
and that prolonged cold storage of cabbage could have allowed a small amount
of initial contamination to grow. Unlike other foodborne pathogens, Listeria
can flourish in cold conditions.
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- Goodridge said another puzzling aspect of the cantaloupe
Listeria outbreak is that four different pulsed-field gel electrophoresis
(PFGE) profiles have been identified, falling into two distinct serotypes,
which could suggest multiple contamination events or a contamination event
from multiple sources, such as different animals.
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- The size and lethal nature of the Listeria outbreak is
surprising, Goodridge said, adding, "And all this involving a commodity
[cantaloupe] that had not previously been implicated in outbreaks of listeriosis."
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- Listeria contamination in cantaloupe, along with an even
more recent recall of California lettuce for potential Listeria contamination,
might prompt the FDA to revisit its Listeria risk assessment for fresh
produce, which is currently considered a low-risk food category, Goodridge
said. On Sep 29 True Leaf Farms of San Juan Bautista, Calif., recalled
90 cartons of chopped romaine lettuce after a random check of a single
bag turned up L monocytogenes. No illnesses have been reported. The products
were shipped to a distributor in Oregon that sent them to at least two
other states, Washington and Idaho.
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- It's too soon to predict how the Listeria outbreak might
affect produce companies, Goodridge said. While the overall produce industry
might not be hurt by the events, the cantaloupe industry will likely suffer
financial fallout, because many people can't or don't distinguish between
growing areas, though some who are now avoiding cantaloupe might forget
about the outbreak by the next season's harvest.
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- "The real concern is the fact that the cantaloupe
industry in Colorado is very small and typically family run, and some growers
are now deciding whether or not to grow cantaloupes next year because of
the outbreak," Goodridge added.
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- http://www.cidrap.umn.edu/cidrap/content/fs/food-disease/news/oct0511listeria-br.html
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- See also:
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- Sep 19 FDA press release
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- Oct 4 CDC outbreak update
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- Jan 27, 1983, N Engl J Med report on Canadian Listeria
outbreak
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- Sep 29 FDA recall notice
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- Patricia A. Doyle DVM, PhD Bus Admin, Tropical Agricultural
Economics Univ of West Indies Please visit my "Emerging Diseases"
message board at:<http://www.emergingdisease.org/phpbb/index.php>http://www.emergingdisease.org/phpbb/index.php Also
my new website: <http://drpdoyle.tripod.com/>http://drpdoyle.tripod.com/ Zhan
le Devlesa tai sastimasa Go with God and in Good Health
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