USDA Misleading American Public about Beef Safety
by Michael Greger, M.D.
Welcome to the world of bovine spongiform encephalopathy
(BSE), or Mad Cow disease. The pathogen thought responsible for this
disease is not a virus, not a fungus, not a bacterium, but thought to be a
prion, an infectious protein. Because of their unique structure, prions
are practically indestructible. They can remain infectious for years in
the soil. They are not adequately destroyed by cooking, canning, freezing,
usable doses of radiation, digestive enzymes, or stomach acid. Even heat
sterilization, domestic bleach, and formaldehyde sterilization have little
or no effect. One study raised the disturbing question of whether even
incineration could guarantee the inactivation of prions. That study was
performed by Paul Brown, medical director for the U.S. Public Health
Service, who found prions could remain infectious even after exposure to
temperatures over a thousand degrees Fahrenheit. That's hot enough to melt
lead. Prions have been called the smallest, most lethal biological
entities in the world.
It is perhaps not surprising that U.S. cattle have Mad
Cow disease given that certain cannibalistic practices of feeding
slaughterhouse waste to livestock have been allowed to continue. What is
surprising, given the inadequacy of our surveillance program, is that we
found a case at all. Europe and Japan follow World Health Organization
guidelines and test every downer cow for Mad Cow disease. In contrast, the
U.S. has tested less than 2% of downers over the last decade. (Downers are
cattle too sick or injured to make it to the slaughterhouse on their own
legs.) In 2003 we increased that testing, but only to about 10%.
Regardless of whether downer cows are tested or not, most of these animals
end up on our dinner plates.
The discovery of a case of Mad Cow disease in the U.S.
highlights how ineffective current safeguards are in North America. The
U.S. banned the feeding of the muscles and bones of most animals to cows
and sheep back in 1997, but, unlike Europe, left gaping loopholes in the
law. For example, blood is currently exempted from the U.S. feed
regulations. You can still collect cow's blood at the
slaughterhouse and feed it to calves. In modern agribusiness, calves may
be removed from their mothers immediately after birth, so the calves are
fed milk replacer, which is often supplemented with cow blood protein.
Weaned calves and young pigs may also have cattle blood sprayed directly
on their feed to save money on feed costs. The outdated notion that blood
cannot transmit the infection is no longer tenable given our current
understanding of prions.
The U.S. feed regulations also still allow the feeding
of rendered cattle remains to pigs, for example, and then the pig remains
can be fed back to cattle. Or rendered cattle remains can be fed to
chickens and then the chicken litter, or manure, can be legally fed back
to the cows. So the fact that the most infectious tissues of the recently
reported U.S. Mad Cow case – the brain, spinal cord, and intestines – were
removed from this animal and not sent to rendering is not necessarily
reassuring given that contaminated tissues are routinely still fed to
pigs, chickens, and other animals who may cycle the disease back to cows,
or perhaps even carry the deadly prions directly to human consumers.
Even with the loopholes closed, though, the feed ban
will only be as effective as its enforcement. Hundreds of feed mills and
rendering plants have violated the feed ban regulation. Last year the
United States General Accounting Office (GAO) released a report on the
inadequacy of our defenses against Mad Cow disease and concluded that the
FDA 's failure to enforce the feed ban may already have "placed U.S. herds
and, in turn, the human food supply at risk."
In Canada, authorities were at least able to reassure
the public that the infected downer cow they discovered was excluded from
the human food chain and only rendered into animal feed. U.S. officials
don't seem to be able to offer the same reassurance, as the Mad Cow we
discovered may very well have been ground into hamburger. How then,
can the USDA and the beef industry insist that the
American beef supply is still safe? They argue that the infectious prions
that cause the disease are only found in the brain and nervous tissue, not
in the muscles, i.e. not in the meat. This can be viewed as misleading on
First, Americans do eat bovine central nervous system
tissue. The GAO report noted, for example, that beef stock, beef extract,
and beef flavoring are frequently made by boiling the skeletal remains of
the animals, including the spinal column. According to the consumer
advocacy organization Center for Science in the Public Interest, spinal
cord contamination may also be found in U.S. hot dogs, hamburgers, pizza
toppings, and taco fillings. In fact, a 2002 USDA survey showed that
approximately 35 percent of high risk meat products tested positive for
central nervous system tissues. Even if Americans just stick to steak,
though, they may not be shielded from risk. There are a number of ways the
muscle tissue can get contaminated by potentially highly infectious brain
or spinal cord tissue. For example, the head trauma caused by the stun
guns used to kill the animals prior to slaughter commonly blasts tiny
fragments of brain throughout the bodies of these animals – causing emboli
of brain tissue to lodge in the lungs, muscles and other tissues.
Even without nervous tissue contamination, though, there
is now evidence that the muscle tissue itself might be infectious. Dr.
Stanley Prusiner, the scientist who won the Nobel Prize in Medicine for
his discovery of prions, proved last year that prions can build up in
muscle tissue, a finding confirmed by follow-up studies in Germany
published in May. And just last month, published in the New England
Journal of Medicine, Swiss scientists found prions in the muscles of human
CJD (Mad Cow) victims on autopsy. Eight out of the 32 muscle samples
turned up positive for the deadly prions.
Despite these shortcomings, Secretary of the US
Department of Agriculture (USDA), Ann Veneman, and the state of
Washington's governor, Gary Locke, both assured the public that that beef
remains safe for consumption in our state and across the country, and they
were still having beef for Christmas – reminiscent of the 1990 fiasco in
which the British agriculture minister appeared on TV urging his
4-year-old daughter to eat a hamburger. Four years later, young people in
Britain were dying from an invariably fatal neurodegenerative disease
called variant Creutzfeldt-Jakob Disease (CJD) – the human equivalent of
Mad Cow disease – which they contracted through the consumption of
infected beef. With an incubation period up to decades long, no one knows
how high the final human death toll will be.
One of the problems, as many English pundits saw it, is
that the British Ministry of Agriculture represented the interests of both
consumers and the beef industry. A similar conflict of interest exists
here in the United States. The mandate of the USDA is to promote
agricultural products, but also to protect consumer health. Secretary
Veneman herself appointed Dale Moore, former chief lobbyist for the
National Cattlemen's Beef Association, as her chief of staff. In the end
I'm afraid this crisis may show to what length governments will go to
prevent financial harm to powerful lobbies in general, and in doing so
risk immeasurable harm to those they claim to represent.
For more information from Dr. Greger, please see my June
2003 Newsletter article, “Cure Your ‘Beef Habit’ Today with a Little Mad
Michael Greger, MD, is a graduate of the Cornell
University School of Agriculture and the Tufts University School of
Medicine. Dr. Greger has been speaking publicly about Mad Cow disease
since 1993. He debated National Cattlemen's Beef Association Director Gary
Weber before the FDA and was invited as an expert witness at the infamous
Oprah Winfrey "meat defamation" trial. He has contributed to many books
and articles on the subject, continues to lecture extensively, and
currently coordinates the Mad Cow disease website for the Organic
Consumers Association. Dr. Greger can be reached for media inquiries at
(617) 524-8064 or [email protected]
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