UNIVERSITY PARK, Pa. -- Bovine spongiform encephalopathy (BSE), better known as "mad cow disease," is front-page news in the U.S. as European countries struggle to control the disease's spread in their cattle. But an expert in Penn State's College of Agricultural Sciences says American shoppers don't have to worry when buying beef.

"The worst may be over for the United States and Europe," says Lawrence Hutchinson, professor of veterinary science. "Corrective measures seem to be working. In North America, we've prohibited animal byproducts in feed, and banned importing these for any use in this country.

We think those two barriers prevented animals in the United States from being exposed to BSE. "We also examine any animals that sicken or die of diseases of the brain or nervous system," he says. "In every case where the cause isn't known, samples of the animal are tested at the National Animal Disease Center in Iowa. To date, of more than 17,000 samples submitted, all have been negative."

Hutchinson says BSE in the United Kingdom has dropped from more than 24,000 cases in the peak year (1994) to about 1,300 cases last year, thanks to stringent quarantine and culling tactics, combined with the prohibition of all animal byproducts in cattle feed. Because the disease has an incubation period of two to eight years, the control measures should finally be taking hold. But projections for BSE's future, he says, are hard to predict.

"At this point, we feel very good about the fact that we're not finding any signs of disease, so meat products raised here in the United States are very safe from BSE," Hutchinson says. "But we have to be very concerned when we see it moving out of England and into other European countries. With world trade being so diverse today, it takes constant vigilance to keep it from coming in. British experts feel they will continue to have sporadic cases for the next four or five years. They're very hopeful that within five years all of the living animals that may be incubating this disease will either have been destroyed or identified as positive."

BSE originated in Great Britain when dairy cattle were fed meat and bone meal rendered from sheep carcasses infected with scrapie, a spongiform encephalopathy that occurs in certain sheep breeds. Hutchinson explains that, while the disease sprang from improper sanitary procedures, the accepted practice of feeding rendered parts to cattle is effective and efficient.

"Cattle feed contains rendered carcasses for two reasons," Hutchinson says. "One, we can make efficient use of something that would otherwise have to go into landfills and pollute soil. Rendered byproducts also contain proteins that are valuable in cattle diets. However, the growth of BSE has made this a poor practice, so in recent years feeding any ruminant protein source to cattle in the United States has been prohibited."

Hutchinson says consumers who still worry about the safety of beef can count on an additional reassurance. "Even in areas where BSE is prevalent, we think that the meat itself is not the problem," he says. "It's the contamination of the meat with brain or spinal cord tissue. But most cuts of beef that are purely beef muscle are very unlikely to be contaminated. In a BSE-free country such as the United States, consumers enjoying beef muscle cuts such as roasts and steaks can be well assured that BSE is not present in their beef."

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EDITORS: For more information, contact Lawrence Hutchinson at 814-863-5938.

Contacts: Gary Abdullah gxa2@psu.edu 814-863-2708 814-865-1068 fax