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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 two counts.
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 Cow."
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] .
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 two counts.
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 Cow."
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] .
