FSnet Aug. 31/08 -- II
BARFBLOG: 17
confirmed and suspected dead in Canadian listeria outbreak
Listeria -
protecting your pregnancy
Trans Ocean
Products recalls "Cracked Pepper Style Smoked Salmon" LOT No
54933-2 because of possible health risks
Outbreak of
severe diarrheal illness in Northeastern OKLAHOMA
OKLAHOMA:
Amid E. coli outbreak, Locust Grove buffet still finds
support
FDA's mobile
field lab in Salinas to do research
KANSAS CITY:
Are radiation treatments for salad greens a good idea? NO
COLUMN:
Irradiating lettuce will save kidsí lives
OP-ED:
Grass-fed vs grain-fed beef and the Holy Grail: A literature
review
how to
subscribe
BARFBLOG: 17
confirmed and suspected dead in Canadian listeria outbreak
31.aug.08
barfblog
Doug Powell
http://barfblog.foodsafety.ksu.edu/2008/08/articles/listeria-1/17-confirmed-and-suspected-dead-in-canadian-listeria-outbreak/index.html
The listeria outbreak in Canada goes from bad to worse as
authorities announced Sunday afternoon (Aug. 31/08) there
are now 11 confirmed and 6 suspected deaths linked to
consumption of Maple Leaf deli meats; further, 33 are
confirmed ill and another 25 are suspected of being ill with
the outbreak strain. However, no comprehensive timeline for
the onset of illnesses has been provided.
http://www.phac-aspc.gc.ca/alert-alerte/listeria/listeria_2008-eng.php
The developments over the past week are difficult to keep
straight. As journalists probe how this happened ñ how the
risk of Listeria monocytogenes was managed ñ a number of
revelations have emerged:
ï employees are alleging that sanitation at the suspect
plant was substandard prior to the outbreak and that daily
cleaning procedures were not consistently followed or
thorough enough;
http://cnews.canoe.ca/CNEWS/Canada/2008/08/30/6616136-sun.html
ï U.S. Department of Agriculture audits found that 19 of 20
Canadian plants were not complying with sanitation
standards, while Canadian inspectors were not always aware
of their duties, "and were not well trained in the
performance of their inspection tasks;" Canadian regulators
urged the Americans to soften their language;
http://www.theglobeandmail.com/servlet/story/LAC.20080830.MEATUSDA30/TPStory/National
ï Rick Holley of the University of Manitoba said Canada
lacks the surveillance systems that could lead to better
detection of foodborne illnesses, in stark contrast to the
United States, which takes a much more active approach to
addressing food safety through the FoodNet system.
http://www.theglobeandmail.com/servlet/story/RTGAM.20080829.wmeat30/BNStory/National/?page=rss&id=RTGAM.20080829.wmeat30
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5714a2.htm
ï until Friday, when David Williams, Ontario's chief medical
officer of health, revealed that most of the fatalities in
Ontario occurred in July, no details had been released on
when individuals died or when they first became sick;
http://www.theglobeandmail.com/servlet/story/RTGAM.20080829.wmeat30/BNStory/National/?page=rss&id=RTGAM.20080829.wmeat30
ï a separate outbreak of listeria in cheese has emerged in
Quebec sickeneing 47 people and leading to the suspension of
product sales from the ‘le aux Grues cheese company;
http://www.canada.com/montrealgazette/news/story.html?id=6247dc3e-565f-4517-ac44-2f1f63cb71e0
ï an additional separate outbreak of Salmonella in cheese in
Quebec has killed one and sickened at least 87 others and
lead to additional recalls of three cheeses manufactured by
Fromages La Chaudiere Inc.; and,
http://www.nationalpost.com/news/canada/story.html?id=756746
ï Canadaís minister of agriculture and agri-food, Gerry
Ritz, held a news conference Thursday to assure Canadians
"our food safety system is the best in the world" and that
work will continue to improve it.
http://www.northumberlandtoday.com/ArticleDisplay.aspx?e=1177244
Listeria -
protecting your pregnancy
30.aug.08
Public Health Agency of Canada
http://www.marketwatch.com/news/story/listeria---protecting-your-pregnancy/story.aspx?guid=%7B82567C6A-9348-4F56-B6D9-056B35D1F2CD%7D&dist=hppr
OTTAWA, ONTARIO -- Recent news about an outbreak of listeria
may have raised concerns about your pregnancy and the safety
of the food you eat.
Listeriosis is a rare but serious infection that is caused
by consuming a type of bacterium called Listeria
monocytogenes (commonly called listeria) that is sometimes
found in food, water and soil.
Pregnant women are at far greater risk of developing
listeriosis than most adults. A woman who develops
listeriosis during the first three months of pregnancy may
miscarry. If she develops the infection later in the
pregnancy, she can pass the infection onto her fetus,
resulting in premature delivery, stillbirth or a very sick
newborn.
When a listeriosis infection occurs during pregnancy,
antibiotics given promptly to the pregnant woman can often
prevent infection of the fetus or newborn.
To protect yourself from listeria or other disease-causing
bacteria, pregnant women should avoid:
- Non-dried deli meats including cold cuts, hot dogs and
smoked salmon, and undercooked meat, poultry, and seafood;
- Raw, unpasteurised milk and dairy products, or foods made
from it such as raw milk cheese, particularly soft and
semi-soft cheeses such as Brie or Camembert;
- Raw sprouts, especially alfalfa sprouts;
- Raw fish, especially shellfish such as oysters and clams;
- Foods made with raw or lightly cooked eggs (for example,
homemade Caesar vinaigrette); and
- Unpasteurized juices, such as unpasteurized apple cider.
In addition, always cook raw food from animal sources well
(such as beef and poultry), keep uncooked meats separate
from other foods, wash hands, cooking utensils and cooking
surfaces well after handling uncooked food, and wash raw
vegetables (especially pre-cut and ready-to-eat vegetables)
thoroughly before eating.
You can check the listeria food recall list at
www.inspection.gc.ca or by calling 1-800-442-2342/TTY
1-800-465-7735. If there is food that you have doubts about,
throw it out or return it to the store.
Testing for listeriosis should only be done on individuals
who are displaying symptoms, therefore it is important that
if you have a persistent fever with any of the following
symptoms that you contact your health care provider
immediately:
- nausea;
- vomiting;
- headache;
- constipation;
- diarrhea; and,
- stiff neck.
Symptoms usually appear within 2 to 30 days and up to 70
days after eating contaminated food.
You can learn more about the recent listeriosis outbreak
online at
http://www.phac-aspc.gc.ca/media/nr-rp/index-eng.php or by
calling 1-800-O-Canada.
Trans Ocean
Products recalls "Cracked Pepper Style Smoked Salmon" LOT No
54933-2 because of possible health risks
31.aug.08
Trans-Ocean Products, Inc.
U.S. Food and Drug Administration
http://www.fda.gov/oc/po/firmrecalls/transocean08_08.html
BELLINGHAM, WASHINGTON ññ Trans-Ocean Products, Inc. of
Bellingham, Washington is recalling its 4 ounce Cracked
Pepper Style Smoked Salmon Lot No 54933-2 because it has the
potential to be contaminated with Listeria monocytogenes, an
organism, which can cause serious and sometimes fatal
infections in young children, frail or elderly people, and
others with weakened immune systems. Although healthy
individuals may suffer only short-term symptoms such as high
fever, severe headache, stiffness, nausea, abdominal pain
and diarrhea, Listeria infection can cause miscarriages and
stillbirths among pregnant women.
Cracked Pepper Style Smoked Salmon, 4 ounce packages were
distributed to three supermarket chains in seven states:
Brookshire Brothers in Texas and Louisiana; Price Choppers
in New York, Pennsylvania, Massachusetts and Vermont; and
Giant Eagle in Ohio and Pennsylvania.
The product is sliced cold-smoked salmon with black pepper.
It is vacuum packaged in a resealable purple plastic pouch
and bears the brand name Trans Ocean Products.The lot number
is ink jetted on the back panel of the package, just right
of center.
No illnesses have been reported to date in connection with
this problem.
The potential for contamination was noted after routine
testing by Trans-Ocean Products revealed the presence of
Listeria monocytogenes in one 4 ounce package of Cracked
Pepper Style Smoked Salmon.
Distribution of the product has been suspended while the FDA
and Trans-Ocean Products investigate the source of the
problem.
Consumers that have purchased Trans Ocean ProductsCracked
Pepper Style Smoked Salmon are urged to return them to the
place of purchase for a full refund.
Consumers with questions may contact Trans-Ocean Products.
Call (800) 290-2722 Monday ñ Friday 6AM to 5PM. Over the
Labor Day weekend call (360) 739-4181.
Outbreak of
severe diarrheal illness in Northeastern OKLAHOMA
30.aug.08
Oklahoma State Department of Health
http://www.ok.gov/health/Organization/Office_of_Communications/News_Releases/2008_News_Releases/Situation_Update_No_6_-_Outbreak_of_Severe_Diarrheal_Illness_in_Northeastern_Oklahoma.html
http://barfblog.foodsafety.ksu.edu/2008/08/articles/e-coli/search-for-e-coli-o111-source-continues-in-oklahoma-1-dead-175-sick/index.html
The Oklahoma State Department of Health (OSDH) reports today
that at least 176 persons have become ill as a result of the
E. coli 0111 outbreak in northeastern Oklahoma. Cases
include 128 adults and 48 children. Federal and state health
officials say E. coli O111 is a rare type not normally
associated with an outbreak this large.
OSDH disease investigators, along with staff from Tulsa
Health Department and area local county health departments,
have interviewed more than 450 persons in an effort to
identify the source of the outbreak. Interviews continue
this weekend.
While the source has not yet been identified, health
officials continue to focus on the Country Cottage
restaurant in Locust Grove, OK, after interviews with cases
indicated most had eaten there during the time period Aug.
15 through Aug. 23. The restaurant is closed while the
investigation continues. Not all persons who ate at the
restaurant have become ill. No other restaurant or food
service outlet in the area has been linked to the outbreak.
OSDH laboratory analysis of water samples taken from a
private well on the restaurant property is continuing,
however, health officials believe it is unlikely that any
well water contamination is the source of the outbreak.
Where available in northeastern Oklahoma, the public may
call 2-1-1 for more information about the outbreak.
Additional information is also on the Oklahoma State
Department of Healthís Web site at www.health.ok.gov. Click
on ìCurrent Features ñ Severe Diarrheal Illness Outbreak.î
OKLAHOMA:
Amid E. coli outbreak, Locust Grove buffet still finds
support
31.aug.08
News OK
Sheila Stogsdill and John David Sutter
http://newsok.com/amid-e.-coli-outbreak-locust-grove-buffet-still-finds-support/article/3290756/?tm=1220158410
LOCUST GROVE -- Residents of this rural Mayes County
community are split over an iconic local restaurant that
state officials say is the source of a deadly E. coli
outbreak in the area.
Some residents are angry at the restaurant over the
possibility that it caused the intestinal illness outbreak,
which has resulted in at least 146 illnesses and one death.
At least 42 children have gotten sick.
Others are offering their support to the restaurant and its
owners, Linda and Dale Moore, who are said to be in a state
of mourning over the illnesses of their friends and
townspeople and also of their beloved restaurant.
Through it all, locals appear to remember that since 1986,
Country Cottage has been a cornerstone of this town's
identity.
"The entire community has just really rallied,î said Amanda
Clinton, a distant cousin of the Moores who is acting as
their spokeswoman.
"They've really come together in this difficult time, not
just to support the owners, but to support those with family
members who are sick.î
A petition has been started at the local Git-N-Split
convenience store to try to keep the restaurant open.
Clinton said the petition has 300 signatures.
Clinton said both of the Moore's two children worked at the
restaurant as co-managers. And after 22 years in the
business, Linda Moore "still rolls back up her sleeves and
helps them cook,î she said.
Other people in Locust Grove blame the restaurant for
causing illnesses and bringing bad publicity to their town.
The town's other restaurants say they're losing business
over the ordeal, even though state health officials have
said their investigation is focused on Country Cottage.
Jerry Troglin of Locust Grove said he doesn't plan to go to
the restaurant again after he was hospitalized in connection
with the outbreak.
FDA's mobile
field lab in Salinas to do research
30.aug.08
The Salinas Californian
Dawn Withers
http://www.thecalifornian.com/apps/pbcs.dll/article?AID=/20080830/NEWS01/808300325
The U.S. Food and Drug Administration has brought a
state-of-the-art mobile laboratory to Salinas to conduct
field research.
The microbiology mobile laboratory is in Salinas until Sept.
19 to examine fresh produce for salmonella and E. coli
O157:H7 contamination, said FDA spokeswoman Mary Ellen
Taylor.
"FDA will review the data and share with industry partners,"
Taylor said of whatever data researchers acquire through
their work in the lab.
The lab is designed for non-agricultural uses and has been
in operation since 2005, going to places such as New Orleans
after Hurricane Katrina, where it was used to test water
quality of shellfish growing beds "to ensure its safety for
shellfish harvest," Taylor said in an e-mail.
The lab consists of two modified 44-foot house trailers and
a modified 34-foot motorhome customized as an administrative
support vehicle. The lab has been outfitted with a
generator, fresh water and waste water tanks, bathroom,
kitchen and four computer work stations for staff
scientists.
Taylor said the mobile lab complex cost $3 million.
The lab is part of a Homeland Security directive aimed at
defending agriculture and the nation's food system from
terrorist attacks, major disasters and other emergencies.
The lab has customized equipment to handle various
emergencies, such as chemical contamination.
KANSAS CITY:
Are radiation treatments for salad greens a good idea? NO
31.aug.08
Kansas City Star
http://www.kansascity.com/273/story/774906.html
Kirk James Murphy writes we donít have to swallow the lie
that irradiation would prevent most cases of food-borne
illness greens may carry.
The majority of food-borne illness linked to greens come
from viruses, not bacteria. Irradiation wonít kill the
viruses ó but it does increase the greensí shelf-life. Gee ó
wonder what the real agenda is?
We didnít evolve consuming foods blasted by industrial
radiation strong enough to kill off E. Coli and delay the
plant from spoiling. Instead, we evolved eating foods that
need to have germs ó like E. Coli ó washed off them in the
kitchen sink. Thatís why for centuries humans have observed
that washing food can decrease illness.
Industry has faith it can make more money blasting food with
high-strength radiation than it would make if it actually
had to carefully prepare food and throw away spoiled meat,
poultry, fish and produce.
COLUMN:
Irradiating lettuce will save kidsí lives
31.aug.08
Canada Free Press
Dennis Avery
http://canadafreepress.com/index.php/article/4745
For years, our Center has been demanding irradiation for
spinach, lettuce, and other high-risk produceóto kill the
food-borne bacteria that present a last big preventable risk
in our food supply. On August 22, the Food and Drug
Administration granted our plea.
FDA permission to irradiate produce is the biggest step
forward in U.S. food safety since irradiation was approved
for meat (read hamburger) in 1990. That followed dozens of
needless ìburger deathsî due to the rare-but-vicious E. coli
O157 bacteria.
Thereís a problem, however: scare-mongers have warned the
public that irradiation itself is not safe. Weíre not even
irradiating much of our hamburger, even as recalls continue
to warn us of the danger.
One scare-mongeróa former professor of environmental
medicineósaid, ìEvery man, woman and child who takes a bite
of irradiated food increases their chance of getting
cancer.î Could he say that publicly without evidence? He
could, and the papers quoted him. The truth, based on
thousands of studies: Irradiation does not create dangerous
cancer-causing organisms, nor does it make the food
radioactive.
ìIn 2006, there were an estimated 50 billion servings of
green. leafy salads served in this country, and there were
approximately 1,200 people made ill,î says Sam Beattie of
Iowa State. Our bacterial risks for fortunately lowóbut they
are not zero. Irradiation can make them nearly zero.
The Centers for Disease Control estimates that irradiation
of high risk foods--certainly including hamburger, poultry,
spinach and lettuce--could prevent up to a million cases of
food poisoning per year, more than 6,000 catastrophic
illnesses, and hundreds of American deathsómostly children.
Remember the people who died from eating spinach
contaminated with E. coli O157 a couple of years ago? It was
organically-grown spinach, carefully washed and packed in a
state-approved processing facility. But organic systems and
washing donít eliminate the bacteria! Authorities, after the
fact, found cattle in the region, a potential source of
O157óand evidence that wild pigs could have carried the
bacteria through the fence, where they snacked on the
spinach. But dangerous bacteria always surround usóin the
soil beneath our feet, and in the air we breathe. Organic
farmers brag about using manure, which after all spreads
dangerous bacteria. Fresh produce is not cooked, as meats
are, so thereís no ìkill step.î
Can food processors use irradiation to pass along bad food?
No. Irradiation kills only rapidly growing cellsóthose of
insects and bacteria. As a bonus, the spoilage bacteria are
killed too, so produce can be left to ripen longer. Itís not
that irradiation makes the food taste better, but it gives
farmers the chance to successfully market better-tasting
produce. Repeated studies have confirmed that irradiation
cannot mask off-flavors or the smell of spoiled foods.
What about irradiation destroying food value? Irradiation
has less impact on nutritive factors than canning or cooking
because it produces virtually no heat.
If youíre uncomfortable with cobalt-60 irradiation, the
industry also offers ìelectronic pasteurization.î Thatís
like putting your food through a low-power microwave, but it
also kills any insects or bacteria.
By rights, the food industry should charge a premium for
irradiated food. Its safety and peak flavors are benefits we
can rely on and even taste. Meanwhile, we keep spending big
money to ìbuy organicî as still another studyóthis one from
the University of Copenhagenófound no demonstrable benefit
from organic foods.
It took us a while to get used to seat belts and pasteurized
milk, too, but itís time to start relying on the
science-based safety of irradiation.
Dennis T. Avery, is a senior fellow with the Hudson
Institute in Washington. Dennis is the Director for Global
Food Issues
([url=http://www.cgfi.org]http://www.cgfi.org[/url]). He was
formerly a senior analyst for the Department of State.
OP-ED:
Grass-fed vs grain-fed beef and the Holy Grail: A literature
review
30.aug.08
Marler Blog
Bill Marler
http://www.marlerblog.com/articles/lawyer-oped/
Several people have commented that switching from grain to
grass feeding could be one of the solutions to the problem
with foodborne pathogens in cattle and other livestock.
Quotes like these are becoming more common on the Internet
and in recent media reports:
ìProducts from grass-fed animals are safer than food from
conventionally-raised animals.î Eatwild, 2008
ìResearch has shown that the strains of E. coli most
devastating to humans are the product of feedlots, not cows.
This is due to the animals being forced to eat an unnatural
diet, and not their natural choice, grass.î Grass-Fed Beef:
Safer and Healthier, Animal Welfare Approved, June 15, 2008
If true, changing the cowís diet would be such a simple and
cheap management practice to implement. Have we found the
Holy Grail for food safety? Below is some research I did on
the topic.
OVERVIEW
ï Identification of on-farm management practices that would
reduce or eliminate foodborne pathogens in cattle and other
livestock (including diet changes) is an active area of
research, but many study results are inconclusive. E. coli
O157:H7, Campylobacter, Salmonella, and other dangerous
pathogens have been repeatedly isolated from both grass and
grain fed livestock, and the studies show conflicting
results regarding whether the levels of pathogens are
higher, lower, or the same when animals are fed grass- or
grain-based diets.
ï There is no clear and consistent definition in the
literature of ìgrass-fed,î but the majority of papers
describe animals that are on pasture or confined, but
receiving only hay-based diets. Last year, the USDA
Agricultural Marketing Service issued a standard for grass
(forage) fed marketing claims. More research on this topic
is needed that compares rates of foodborne pathogens among
grain and grass fed animals using a specific definition such
as the USDA standard or other accepted definition.
ï The original study by Diez-Gonzalez published in Science
in 1998, and since cited numerous times in the literature
and media, suggested that cattle could be fed hay for a
brief period before slaughter to significantly reduce the
risk of foodborne E. coli infection. They based this
conclusion on a hypothesis that grain feeding increases acid
resistance of E. coli in cattle. Although they showed
increased acid resistance in E. coli from grain-fed cattle,
but the sample size was small, and they used ìgenericî E.
coli stains, not E. coli O157:H7.
ï Studies by other researchers worldwide have since found
little difference in acid resistant E. coli O157:H7 among
grain- verses grass-fed cattle, and some even found more E.
coli O157:H7 shed by grass-fed animals.
ï It has been discovered that E. coli O157:H7 and Salmonella
can rapidly switch from being ìacid sensitiveî to ìacid
resistantî within minutes after entering an acidic
environment (such as the human stomach). Thus, even if the
grass-fed/E. coli acid-resistance hypothesis were true,
manipulating the diet may not have any effect since
pathogens can adapt quickly to new environments like the
human stomach.
ï Outbreaks have traced back to grass-fed and pastured
animals, as well as animals in feedlots. Notably, the E.
coli O157:H7 spinach outbreak strain in 2006 was isolated
from grass-fed cattle. Another outbreak of E. coli O157:H7
was linked recently to raw milk and colostrum from cattle
raised organically on grass.
ï In summary, the scientific evidence at this time does not
support a broad conclusion that grass feeding significantly
and consistently reduces the risk of E. coli O157:H7 or
other dangerous foodborne pathogens entering the food chain.
However, more research is needed into the influence of food
animal diets. For example, preliminary experimental data
shows a possible association between feeding dried
distillerís grains and shedding of E. coli O157:H7 in cattle
feces.
INTRODUCTION
A systematic approach is necessary to combat the emerging
challenges in food safety such as the unexplained ìuptickî
of E. coli O157:H7 outbreaks and recalls linked to beef
products. Interventions to protect the food supply should
ideally occur across the continuum from ìfarm to fork.î The
ìHoly Grailî of pre-harvest (farm-level) food safety would
be to find an effective, affordable, and practical means to
prevent or reduce food animals from shedding foodborne
pathogens in the first place so the dangerous bacteria never
enter the human food chain. Since cattle or other livestock
may be located near drinking water sources or vegetable
crops, a farm-level intervention could also help to protect
nearby water and crops from contamination by manure via
runoff, transport by wildlife/insects, or other mechanisms.
Oliver et al (2008) published a comprehensive review of
developments and future outlooks for pre-harvest food safety
this month. Examples of potential farm-level management
practices that have been studied for E. coli O157:H7 and
other foodborne pathogens in livestock include:
ï Antibiotics
ï Bacteriophages (viruses of bacteria)
ï Dietary changes
ï Immunization
ï Probiotics or prebiotics in animal rations
ï Sanitation/hygiene (feed, water, environment)
ï Wildlife and insect control
Unfortunately, the best approaches for on-farm control of
foodborne pathogens in livestock remain elusive. No single
management practice, or even a combination of methods, has
proven to be very effective or reliable in preventing
foodborne pathogen colonization in livestock. Clearly,
sanitation including clean feed/water sources and insect
control are important, but difficult to maintain in a farm
environment. Livestock immunizations are not available for
most foodborne pathogens with the exception of an E. coli
O157:H7 vaccine under development (and some ask ìwho would
pay for such a program?î since cattle do not become ill from
E. coli O157). Use of antibiotics is problematic because it
can lead to resistance.
GRASS VERSUS GRAIN FEEDING
Definition of ìGrass-Fedî
The majority of cattle are fed grass or other forage at some
time during their lives. For the purpose of marketing, the
USDA Agricultural Marketing Service issued a voluntary
standard for grass (forage) fed marketing claims last year
that states: ìgrass fed standard states that grass and/or
forage shall be the feed source consumed for the lifetime of
the ruminant animal, with the exception of milk consumed
prior to weaning. The diet shall be derived solely from
forage and animals cannot be fed grain or grain by-products
and must have continuous access to pasture during the
growing season.î
Note that most papers in the literature do not specifically
define grass-fed using this new standard or any other
specific definition, but differentiate, in general, between
animals on forage (grass) only verses diets containing
grain.
The Study that Started the Controversy
The original study that launched the controversy over grain
feeding was published in Science in 1998 by researchers from
Cornell (Diez-Gonzalez et al). They described potential
dietary effects on the acid resistance of E. coli in cattle
fed grain- versus hay-based diets. This study has since been
cited numerous times in the literature and media, but later
studies have not been able to reproduce the findings. This
may be due, in part, to several limitations in the original
study design including: 1) small sample size and 2)
ìGenericî E. coli levels were measured, not E. coli O157:H7.
In 2006, Hancock and Besser wrote a summary of the evidence
surrounding the hypothesis that feeding hay instead of grain
would reduce the problem with E. coli O157:H7, purportedly
because the stomachs of grain-fed cattle are more acidic.
They concluded: ìwhile one cannot rule out a role of cattle
diet on affecting exposure and infectivity of E. coli
O157:H7 to humans, the data available at present demonstrate
that cattle on a wide variety of diets (including 100%
forage diets) are regularly and similarly colonized with
this pathogen.î
Another interesting study from a research group in The
Netherlands discovered that E. coli O157:H7 and Salmonella
can rapidly switch from being ìacid sensitiveî to ìacid
resistantî within minutes after entering an environment with
reduced pH (such as the human stomach). Thus, even if the
grass-fed hypothesis were true, manipulating the diet may
not have any effect since E. coli O157:H7 can adapt quickly
to new environments like the human stomach.
Recent Findings in the Literature
In searching through the literature since Hancock and
Besserís review, several new papers relevant to the
discussion were found.
1. Nutritional aspects of grass-fed beef.
Leheska, J. M., L. D. Thompson, J. C. Howe, E. Hentges, J.
Boyce, J. C. Brooks, B. Shriver, L. Hoover, and M. F.
Miller. 2008. Effects of conventional and grass feeding
systems on the nutrient composition of beef. J Anim Sci.
ï This paper explores the question about whether there are
differences in nutrient composition of grass-fed beef
compared with conventional (grain)-fed beef. Researchers
have previously found higher omega-3 fatty acids and CLA
(conjugated linoleic acid) in forage-fed beef, and lower fat
content overall. Some consumers prefer eating grass-fed meat
because they believe it is ìhealthier,î and/or tastes better
than conventional beef.
ï The authors of this study enrolled only producers that
were marketing grass-fed beef and confirmed that ì100% of
the diets were made up of native grasses, forages, or cut
grasses or forages.î
ï Fatty acid composition of grass-fed and conventional-fed
beef was found to be different, but the authors conclude
ìthe effects of the lipid differences between grass-fed and
conventional raised beef, on human health, remains to be
investigated.î
2. Papers continue to be published about possible effects of
diet on E. coli O157:H7 prevalence and concentration.
For example, a research team from Kansas State University
reported that feeding distillers grains, a co-product of
ethanol production, to feedlot cattle may have a positive
association with fecal shedding of E. coli O157. The
mechanism is unknown, but they hypothesize that the grains
change the ecology of the hindgut where E. coli O157 is most
likely to colonize cattle. The authors report that larger
studies are underway to investigate this possible link.
CONCLUSIONS
In summary, the scientific evidence at this time does not
support a broad conclusion that grass feeding significantly
reduces the risk of E. coli O157:H7 or other dangerous
foodborne pathogens from entering the food chain. However,
more research is needed to better understand the influence
of diet, especially the use of different types of grains in
animal feed.
FSnet is produced by the
International Food Safety Network at Kansas State
University, and is supported at the Gold Fork level by:
Marler Clark.
FSnet is supported at the Sterling Fork level by: CropLife
Canada, Ontario Ministry of Agriculture, Food and Rural
Affairs , New Zealand Food Safety Authority, Monsanto
Canada, and the Ontario Cattlemen's Association.
Fsnet is supported at the Silver-plate Fork level by: The
National Restaurant Association, Unilever, Sholl Group/Green
Giant Fresh, Feedlot Health Management Services, McDonald's,
and Syngenta Crop Protection Canada.
The Food Safety Network presents a unique opportunity to
bring together all those associated with agriculture and
food, to enhance the safety of the food supply. To provide
financial support to the Food Safety Network, please visit
http://www.foodsafety.ksu.edu/en/donations.php. For
information on collaboration or fee-for-service
opportunities, please contact Dr. Doug Powell:
dpowell@ksu.edu
To subscribe to the html version of FSnet, send mail to:
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For more information about the FSnet research program,
please contact:
Dr. Douglas Powell
associate professor
dept. diagnostic medicine/pathobiology
Kansas State University
Manhattan, KS
66506
cell: 785-317-0560
fax: 785-532-4039
dpowell@ksu.edu
http://www.foodsafety.ksu.edu
archived at
http://archives.foodsafety.ksu.edu/fsnet-archives.htm
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