Medical News: General Infectious Disease

Raw Milk Remains a Health Threat

By Michael Smith, MedPage Today
December 17, 2008
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.

WOOSTER, Ohio, Dec. 17 -- Diseases caused by drinking
unpasteurized milk remain an important public health
problem in the U.S., researchers said.

Between 1993 and 2006, there were an average of 5.2 disease
outbreaks a year linked to raw milk, according to Jeffrey
LeJeune, D.V.M., Ph.D., of the Ohio Agricultural Research
and Development Center, here, and Päivi Rajala-Schultz, D.V.M.,
Ph.D., of the College of Veterinary Medicine in Columbus, Ohio.

That's more than double the 2.4 outbreaks a year seen in the
previous 19 years, the researchers said in the Jan. 1, 2009
issue of Clinical Infectious Diseases.

The increase may be partly attributable to better detection
and reporting, but some can be blamed on increased consumption
of raw milk, they argued in an invited review in the journal.

Recent outbreaks of disease that were related to consumption
of unpasteurized milk or dairy products include:


In 2005, 18 cases of infection with Escherichia coli O157:H7,
mostly among children younger than 14, in Oregon and Washington.
Five patients were admitted to the hospital, four of them with
hemolytic uremic syndrome.

In 2007, 29 cases of Salmonella enterica serotype Typhimurium
infection -- including 16 children younger than seven -- were
associated with consumption of raw milk or raw-milk products
in Pennsylvania.

Also in 2007, at least 87 people became ill in Kansas in two
separate outbreaks of campylobacteriosis, both associated with
raw milk.

In 2008, an outbreak of campylobacteriosis in California was
associated with unpasteurized milk and one of the patients
subsequently developed Guillain-Barre syndrome.

Consumption of raw milk has always been common among farm
families, the researchers noted, with 35% to 60% doing so
today. Most say that taste and convenience are the main
reasons they drink raw milk.

A small portion of the general U.S. population also consumes
raw milk, the researchers said, but its sale is illegal in
26 states. Washington, Pennsylvania, Kansas, and California
are among the states that allow it.

"In states where raw milk sales are not allowed, various
schemes have been developed to make raw milk available
to the consumer," the researchers said.

Marketing strategies, they said, include:

Labeling the milk as "animal or pet food"
Publishing a list of states where the sale of raw milk
is allowed
Selling shares in or leasing cows, so that consumers pay
for the care and milking of the cows and get raw milk in
return, avoiding the buying and selling of raw milk per se

Milk in the bovine mammary gland is usually not contaminated
with bacteria, unless the animal has a systemic illness or the
gland itself is infected, they said.

But on a farm, external sources of contamination are plentiful,
the researchers said, so that "even in a healthy animal, by
the time the milk leaves the animal, it may contain numerous
bacterial contaminants."

In pooled farm milk, the frequency of bacterial contamination
is reported to be as high as 8.9% for salmonella species, 6.5%
for Listeria monocytogenes, 3.5% for Shiga toxin-producing E.
coli, 12.3% for Campylobacter jejuni, and 6.1% for Yersinia
enterocolitica.

The demand for raw milk has been growing, as advocates suggest
it is entirely safe and, indeed, more health-giving than
pasteurized milk, the researchers said.

Although the evidence for those positions is poor, members of
the lay public may hold strong views that conflict with
expert opinion on the risks and benefits of raw milk, the
researchers said.

"Clinicians, therefore, are faced with the challenge of
communicating health risks and promoting behavioral changes
among individuals who hold strong opinions about their dietary
selections," they said.

One method that has been proposed to ensure the safety of raw
milk relies on product testing. The authors pointed out,
however, that "product testing cannot ensure safety. Testing
schemes are limited by assay sensitivity...and are complicated
by several factors:

(1) milk contamination occurs sporadically,
(2) contamination may not be evenly distributed in a product,
(3) extremely small amounts are infectious, and
(4) extremely small numbers (below the detectable limit) of
organisms present in the product may proliferate to levels that
reach unacceptable risks after testing."

The study was supported by the Ohio Agricultural Research and
Development Center.

Primary source: Clinical Infectious Diseases
Source reference:
LeJeune, JT, and Rajala-Schultz, PJ
"Unpasteurized milk: a continued public health threat"
Clin Infect Dis 2009; 48: 93-100.
________________________________

Robert Cohen
http://www.notmilk.com