040120 Expert: New Rules Make Beef Safer

Laramie, WY - New federal regulations designed to prevent cattle infected with mad cow disease from entering the food supply should reassure consumers at home and abroad that U.S. beef is safe, a University of Wyoming food- safety expert said.

The regulations were put in place after the nation's first case of mad cow disease, or bovine spongiform encephalopathy, was found last month in a dairy cow slaughtered in Washington state.

"I am confident as a scientist and a consumer who also feeds beef to my family that the system to screen out animals with BSE we have in place in the United States, and the similar system Canada has in place, is working," said Warrie Means, associate professor of animal science.

"The U.S. Department of Agriculture has built several firewalls so that we are not going to have recurring reinfection of animals."

One of the firewalls is a ban since 1997 on feeding to cattle byproducts of cows unable to walk by themselves. The practice of rendering tissue from so-called "downers" back into feed is believed to be a major factor in the BSE outbreak in Great Britain in the 1980s.

Scientists believe that humans who eat brain or spinal matter from an infected cow can develop variant Creutzfeldt-Jakob disease. The incurable disease was blamed for 143 deaths in Britain.

"The 1997 ban coupled with the new prohibition against any downer being allowed into the human food chain is an important protection against BSE being transmitted beyond any currently infected animal and go even further toward making beef absolutely as safe as it can be," Means said, adding that BSE is only one of a number of reasons an animal may be unable to walk.

Since the abnormal proteins that cause mad cow disease are not destroyed by normal cooking or exposure to microwaves, irradiation or sterilization techniques, Means said the surest way to prevent further transmission is to segregate individual animals suspected of being infected.

He also said USDA is banning use of air-injection stunning devices at beef-processing facilities. Such systems use a burst of air to render an animal unconscious just before slaughter.

"But neural tissue can be pushed into muscle tissue when the animal is stunned," Means said, "and since we know that BSE-causing proteins are embedded in neural tissues, discontinuing the use of these stunning systems will ensure that if any infected animal does escape detection in the downer-screening process, infected tissue will not contaminate muscle tissue destined to become meat."

Few large meat processing facilities were still using air-injection systems anyway, and he said there are alternative ways of using tissue from downers so that they do not represent a total financial loss for producers. Downers can be euthanized and rendered into feed for nonruminant animals or turned back into organic material through composting methods, he said.

Another tool to combat bovine disease is a uniform animal identification system, which the USDA is working toward, Means said.

"This gets complicated because calves are often born out on the open range out of anyone's sight, and documenting when they were born can only be done within an accuracy of a few days."

Establishing a general idea of when a cow was born is important to controlling BSE because it is rarely if ever seen in animals under 30 months old.

"It's very difficult to maintain the identity of an animal from the cow-calf operator through the yearling or stocker operator, the feedlot and into the harvest facility," the professor said.

"The animal may change ownership several times, and the ear tags a lot of operators use right now can fall off or be changed. So the industry is moving towards some other means of uniform identification, but we're not quite there yet.”

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