UGA Beef Team: Topics: BSE

POTENTIAL CONSUMER ANSWERS ABOUT MAD COW DISEASE  (1/15/04)

Elizabeth Andress, Ph.D., Extension Food Safety Specialist
Judy A. Harrison, Ph.D., Extension Foods Specialist
Ronnie A. Silcox, Ph.D., Extension Animal Scientist

January 15, 2004

Q: How do beef cattle contract mad cow disease or BSE (bovine spongiform encephalopathy)?
A: Cattle contract BSE from eating feed made from beef byproducts already infected with BSE. These byproducts include spinal column, brain, bone marrow, beef cheeks, tongue and other head meat.

Q: Can humans get BSE?
A: Not exactly. BSE is a disease that affects cattle. BSE is one of several diseases known as Transmissable Spongiform Encephalopathies (TSEs). There are human forms of TSEs which are relatively rare human diseases.  The one which would be considered the human equivalent of BSE is known as New Variant Creutzfeldt-Jakob disease (vCJD). According to the CDC, A BSE epidemic in the United Kingdom reached a peak incidence in January 1993. This outbreak was spread by feeding infected meat and bone meal to cattle. As of December 1, 2003, a total of 153 cases of vCJD had been reported in the world: 143 from the United Kingdom, 6 from France and 1 each from Canada, Ireland, Italy and the United States. The U.S. case was reported in a patient who lived in the United Kingdom before moving to the U.S. Almost all 153 vCJD patients had multiple-year exposures in the United Kingdom between 1980 and 1996 during a large outbreak of BSE among cattle. Also according to CDC, there has not been a case of vCJD that did not have a history of exposure in a country where the cattle disease, BSE, was occurring.  The human disease that is classic, sporadic CJD was first identified in the 1920s and has a worldwide incidence of approximately 1 case per million people each year. Classic CJD has a higher median age (68 years) at death than does vCJD that has occurred in the United Kingdom (28 years). vCJD is caused by the development of large, abnormal proteins in the central nervous system which the body cannot breakdown. vCJD can only be confirmed through examination of brain tissue by biopsy or autopsy. "Probable cases" of vCJD are now diagnosed on the basis of clinical criteria developed in the United Kingdom. No indigenous cases of vCJD have been detected in the U.S. The only case is the one mentioned above, where the person had been living in the United Kingdom prior to moving to the U.S.

Q: What is my risk of getting New Variant Cruetzfeldt-Jakob Disease (vCJD)?
A: The current risk of getting vCJD is extremely small. As of December 1, 2003, only one case of vCJD had been reported in the United States ever.  The patient involved in this case lived in the United Kingdom before moving to the U.S.

Q: Should I eat beef or how do I minimize my risk?
A: It is up to the individual to determine whether or not to consume beef.  Even though the risk at this time is considered very, very small (even negligible by some sources), some consumers may still need to feel they have a way to exercise some control in managing their risks and making decisions. A great deal of research has been done on BSE since it was first discovered in Great Britain in 1986. This research indicates:  

1. The infective agent is found in the brain and spinal tissue of infected cattle.
2. The disease takes 3-8 years to develop in cattle and the infective agent has not been found in cattle under 30 months of age.
3. The infective agent has not been found in beef muscle tissue or milk.

For those who feel they must do something, here are some tips:  

1. Purchase "whole" or "single-muscle" meat cuts. Most steaks and roasts in retail cases come from young animals.
2. If you have concerns about ground meats, buy a "single-muscle" cut of meat, like a roast, and have it ground for you.
3. Avoid variety cuts of meat such as brains and head meat or products containing bone marrow. Oxtail will contain the end of the spinal column.
4. If you have additional concerns, cattle that have consumed vegetarian grain or natural grasses throughout their life have never been exposed to potentially dangerous feed; labels will usually say something like "grass-fed." New safeguards have been instituted by USDA as of January 12, 2004 that will further reduce some of these concerns.  They are outlined in the next two questions.

Q: What is this "advance meat recovery" or AMR we're hearing about, and can it affect the safety of meat products?
A: Some meat in hot dogs, sausages and ground beef, especially in frozen and processed products, has come from a process called "advance meat recovery" (AMR), in which meat is removed from carcasses under pressure without incorporating bone and bone products, if produced properly.  This product has been able to be labeled "meat." A 2002 USDA survey found that AMR meat from 3/4 of the tested plants, however, contained central nervous system tissue. As of December 30, 2003, the USDA announced a new interim rule that says establishments have to ensure process control through verification testing to ensure that neither spinal cord nor dorsal root ganglia is present in the product.  USDA (FSIS) has previously had regulations in place that prohibit spinal cord from being included in products labeled as "meat." The new rule also expands that prohibition to include dorsal root ganglia, clusters of nerve cells connected to the spinal cord along the vertebrae column, in addition to spinal cord tissue. Like spinal cord, the dorsal root ganglia may also contain BSE infectivity if the animal is infected. In addition, because the vertebral column and skull in cattle 30 months and older will be considered inedible, it cannot be used for AMR.  According to the National Cattlemen's Beef Association, "the BSE agent is not found in milk or beef muscle meats used for steaks, roasts and ground beef".

Q: Are there other new rules to protect our beef?
A: USDA instituted some changes on December 20, 2003 and others as of publishing a new Interim Final Rule for some aspects of processing on January 12, 2004.  * Effectively immediately, USDA banned all downer or non-ambulatory cattle from the human food chain.

  * Any cattle tested for BSE by inspectors as part of routine screenings will not be allowed into the food supply until tests confirm it is safe.  
  * USDA is now declaring as "specified risk materials" the skull, brain, trigeminal ganglia, eyes, vertebral column, spinal cord and dorsal root ganglia of cattle over 30 months of age and the small intestine of cattle of all ages, thus prohibiting their use in the human food supply. Tonsils from all cattle are already considered inedible and therefore do not enter the food supply. FSIS will require federally inspected establishments that slaughter cattle to develop, implement, and maintain procedures to remove, segregate, and dispose of these specified risk materials so that they cannot possibly enter the food chain.  
  *  To ensure that portions of the brain are not dislocated into the tissues of the carcass as a consequence of humanely stunning cattle during the slaughter process, FSIS is issuing a regulation to ban the practice of air-injection stunning of animals, used previously as an early step in processing.
  *  USDA will now restrict use of mechanically separated meat in human food.

Q: Is the beef I would buy in Georgia contaminated?
A: It is highly unlikely that Georgia beef would be contaminated from this particular identification of BSE in an animal in the U.S. The herd which contained the cow infected with BSE resides in Washington state, and that herd has been traced back to Canada. 

Q: Does cooking make the meat safe from mad cow disease?
A: No. The odd-shaped protein called a prion that causes the disease cannot be eliminated by heat, freezing or irradiation.

Q: What about the meat in my freezer now?
A: The best we can say is that the meat processed prior to the new interim regulations will contain the same level of risk from BSE that we have been living with until now, which is considered minimal to negligible.

Reminder: The bigger concerns in meat contamination still remain the microbiological hazards and people should not forget to exercise care in the selection, handling, preparation, cooking and cooling of meats and meat products.  Remember, the four basic rules to fight bacteria are still essential:

• Clean
• Separate; don't cross-contaminate
• Cook
• Chill

top