A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Fri 17 Jun 2011
Source: Wisconsin Business [edited]
Laboratory test results show that the _Campylobactor jejuni_bacterium
that caused diarrheal illness among 16 individuals who drank
unpasteurized (raw) milk at a school event early this month in Raymond
was the same bacterial strain found in unpasteurized milk produced at
a local farm, according to officials from the Department of Health
Services (DHS) and Western Racine County Health Department (WRCHD). A
parent had supplied unpasteurized milk from the farm for the school
Stool samples submitted to the WRCHD by ill students and adults were
sent to the State Laboratory of Hygiene where they tested positive for
the bacterium. Department of Agriculture, Trade and Consumer
Protection (DATCP) food inspectors collected milk samples from the
bulk tank at the farm, which tested positive for _Campylobacter
jejuni_. Further testing by the State Hygiene lab showed the bacterial
strains from the stool samples and the milk samples matched.
Additionally, interviews with event attendees revealed that consuming
the unpasteurized milk was statistically associated with illness.
Health officials said that this combination of laboratory and
epidemiological evidence indicates that the illnesses were caused by
the unpasteurized milk consumed at the school event.
The farm did not sell the unpasteurized milk and there was no legal
violation associated with the milk being brought to the school event.
The farm is licensed and in good standing with the Department of
Agriculture, Trade and Consumer Protection.
HealthMap Alerts via ProMED-mail
[Clusters of infection continue to be reported each year caused by
the ingestion of raw milk. Its advocates vehemently argue regarding
the value of the product but the science supporting its use is minimal
at best. Regarding whether raw milk safety and its increased
nutritional value has been "adequately documented by both the USDA and
the FDA, the following is from the FDA in 2004, "Got Milk? Make Sure
Pasteurization, since its adoption in the early 1900s, has been
credited with dramatically reducing illness and death caused by
contaminated milk. But today, some people are passing up pasteurized
milk for what they claim is tastier and healthier "raw milk." Public
health officials couldn't disagree more.
Drinking raw (untreated) milk or eating raw milk products is "like
playing Russian roulette with your health," says John Sheehan,
director of the Food and Drug Administration's Division of Dairy and
Egg Safety. "We see a number of cases of foodborne illness every year
related to the consumption of raw milk."
More than 300 people in the USA got sick from drinking raw milk or
eating cheese made from raw milk in 2001, and nearly 200 became ill
from these products in 2002, according to the CDC.
Raw milk may harbor a host of disease-causing organisms (pathogens),
such as the bacteria _Campylobacter_, _E. coli_, _Listeria_,
_Salmonella_, _Yersinia_, and _Brucella_. Common symptoms of foodborne
illness from many of these types of bacteria include diarrhea, stomach
cramps, fever, headache, vomiting, and exhaustion. Most healthy people
recover from foodborne illness within a short period of time, but
others may have symptoms that are chronic, severe, or
People with weakened immune systems, such as elderly people,
children, and those with certain diseases or conditions, are most at
risk for severe infections from pathogens that may be present in raw
milk. In pregnant women, _Listeria monocytogenes_-caused illness can
result in miscarriage, fetal death, or illness or death of a newborn
infant. _E. coli_ infection has been linked to hemolytic uremic
syndrome, a condition that can cause kidney failure and death.
Some of the diseases that pasteurization can prevent are
tuberculosis, diphtheria, polio, salmonellosis, strep throat, scarlet
fever, and typhoid fever.
Pasteurization and contamination
The pasteurization process uses heat to destroy harmful bacteria
without significantly changing milk's nutritional value or flavor. In
addition to killing disease-causing bacteria, pasteurization destroys
bacteria that cause spoilage, extending the shelf life of milk.
Milk can become contaminated on the farm when animals shed bacteria
into the milk. Cows, goats, and sheep carry bacteria in their
intestines that do not make them sick but can cause illness in people
who consume their untreated milk or milk products.
But pathogens that are shed from animals aren't the only means of
contamination, says Tom Szalkucki, assistant director of the Wisconsin
Center for Dairy Research at the University of Wisconsin-Madison. Cows
can pick up pathogens from the environment just by lying down, giving
germs the opportunity to collect on the udder, the organ from which
milk is secreted. "Think about how many times a cow lays down in a
field or the barn," says Szalkucki. "Even if the barn is cleaned
thoroughly and regularly, it's not steamed. Contamination can take
place because it's not a sterile environment."
The health hype
Raw milk advocates claim that unprocessed milk is healthier because
pasteurization destroys nutrients and the enzymes necessary to absorb
calcium. It also kills beneficial bacteria and is associated with
allergies, arthritis, and other diseases, they say.
This is simply not the case, says Sheehan. Research has shown that
there is no significant difference in the nutritional value of
pasteurized and unpasteurized milk, he says. The caseins, the major
family of milk proteins, are largely unaffected, and any modification
in whey protein that might occur is barely perceptible.
"Milk is a good source of the vitamins thiamine, folate, B-12, and
riboflavin," adds Sheehan, "and pasteurization results in losses of
anywhere from zero to 10 percent for each of these, which most would
consider only a marginal reduction."
While the major nutrients are left unchanged by pasteurization,
vitamin D, which enhances the body's absorption of calcium, is added
to processed milk. Vitamin D is not found in significant levels in raw
"Pasteurization will destroy some enzymes," says Barbara Ingham, PhD,
associate professor, and extension food scientist at the University of
Wisconsin-Madison. "But the enzymes that are naturally present in milk
are bovine enzymes. Our bodies don't use animal enzymes to help
metabolize calcium and other nutrients. Enzymes in the food that we
eat and drink are broken down in the human gastrointestinal tract,"
adds Ingham. "Human bodies rely on our own native enzymes to digest
and metabolize food. Most of the native enzymes of milk survive
pasteurization largely intact," says Sheehan, "including those thought
to have natural antimicrobial properties and those that contribute to
prolonging milk's shelf life." Other enzymes that survive are thought
to play a role in cheese ripening.
Ingham says that pasteurization will destroy some bacteria that may
be helpful in the fermentation of milk into products such as cheese
and yogurt, "but the benefit of destroying the harmful bacteria vastly
outweighs the supposed benefits of retaining those helpful
microorganisms. Plus, by adding the microorganisms that we need for
fermentation, we can assure a consistently high quality product."
Science has not shown a connection between drinking raw milk and
disease prevention. "The small quantities of antibodies in milk are
not absorbed in the human intestinal tract," says Ingham. "And there
is no scientific evidence that raw milk contains an anti-arthritis
factor or that it enhances resistance to other diseases."
Fans of raw milk often cite its creamy rich taste, says Szalkucki,
who adds that it may be creamier because it is not made according to
the standards for processed milk. "If you go to a grocery store and
buy fluid milk, it's been standardized for a certain percentage of
fat, such as 2 percent," he says. "Raw milk is potentially creamier
because it has not been standardized and it has a higher fat
It is a violation of federal law enforced by the FDA to sell raw milk
packaged for consumer use across state lines (interstate commerce).
But each state regulates the sale of raw milk within the state
(intrastate), and some states allow it to be sold. This means that in
some states, dairy operations may sell it to local retail food stores
or to consumers directly from the farm or at agricultural fairs or
other community events, depending on the state law.
In states that prohibit intrastate sales of raw milk, some people
have tried to circumvent the law by "cow sharing," or "cow leasing."
They pay a fee to a farmer to lease or purchase part of a cow in
exchange for raw milk, claiming that they are not actually buying the
milk since they are part owners of the cow. Wisconsin banned
cow-leasing programs after 75 people became infected with
_Campylobacter jejuni_ bacteria in 2001 from drinking unpasteurized
milk obtained through such a program.
Raw milk cheeses
The FDA allows the manufacture and interstate sale of raw milk
cheeses that are aged for at least 60 days at a temperature not less
than 35 deg F (2 deg C). "However, recent research calls into question
the effectiveness of 60-day aging as a means of pathogen reduction,"
The FDA's Center for Food Safety and Applied Nutrition (CFSAN) is
currently examining the safety of raw milk cheeses and plans to
develop a risk profile for these cheeses. This information will help
FDA risk managers make future decisions regarding the regulation of
these products to protect public health.
Ensuring milk safety
The FDA provides oversight for the processing of raw milk into
pasteurized milk, cottage cheese, yogurt, and sour cream under the
National Conference on Interstate Milk Shipments "Grade A" milk
program. This cooperative program between the FDA and the 50 states
and Puerto Rico helps to ensure the uniformity of milk regulations and
the safety of milk and milk products. The program is based on
standards described in the FDA's Pasteurized Milk Ordinance (PMO), a
model code of regulations that can be adopted by the states in their
Under the "Grade A" program, state personnel conduct inspections and
assign ratings, and FDA regional milk specialists audit these ratings,
says Richard Eubanks, MPH, a senior milk sanitation officer on CFSAN's
Milk Safety Team. "It's a rigorous process of inspection and
auditing," he says, and "it covers from cow to carton," starting with
the dairy farm and continuing through the processing and packaging of
products at milk plants. Products that pass inspection may be labeled
The FDA "Grade A" milk program includes pasteurized milk from cows,
goats, sheep, and horses. Raw milk and raw milk cheeses cannot be
labeled "Grade A," since they are not pasteurized and not covered
under the program. - Mod.LL]
[The interactive HealthMap/ProMED map for Wisconsin is available at:
<http://healthmap.org/r/00Pq> - CopyEd.EJP]
Campylobacteriosis, E. coli O157, unpasteurized goat milk - USA: (CO)
Salmonellosis, unpasteurized milk - USA (02): (UT) serotype Newport
Salmonellosis, unpasteurized milk - USA: (UT) 20100517.1616
Campylobacteriosis, unpasteurized milk - USA: (MI ex IN)
Campylobacteriosis, unpasteurized milk - USA (02): (WI)
Campylobacteriosis, unpasteurized milk - USA: (CO) 20090415.1430
Campylobacteriosis, unpasteurized milk - USA (CA) 20080817.2557
Campylobacteriosis, unpasteurized milk - USA (KS) 20071205.3922
Salmonellosis, serotype Typhimurium, raw milk - USA (02): (PA), CDC
Salmonellosis, free unpasteurized milk - USA (PA) (03)
Campylobacteriosis, unpasteurized milk - USA (GA) 20070803.2520
Salmonellosis, free unpasteurized milk - USA (PA) 20070722.2354
Listeriosis, unpasteurized cheese - USA (IN) 20070425.1351
Campylobacteriosis, unpasteurized milk - USA (UT) (02)
Campylobacteriosis, unpasteurized milk - USA (UT) 20070322.1004
Salmonellosis, serotype Typhimurium, raw milk - USA (PA)
E. coli O157, unpasteurized milk, 2005 - USA (WA) 20070302.0741
Foodborne illness, unpasteurized milk - USA (OH) 20060929.2794
E. coli O157, unpasteurized milk - USA (CA) (03) 20060929.2791
E. coli O157, unpasteurized milk - USA (WA): recall 20060929.2790
E. coli O157, unpasteurized milk - USA (CA) (02): background
E. coli O157, unpasteurized milk - USA (CA) 20060922.2706
E. coli O157, unpasteurized milk - USA (OR, WA) (04) 20060121.0199
E. coli O157, unpasteurized milk - USA (OR, WA) 20051216.3622
Salmonellosis, raw milk - USA (Ohio) (03) 20030204.0308
Salmonellosis, raw milk - USA (Ohio) 20030105.0033]
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