Consumers shouldn't be afraid of eating beef in the wake of the report that a cow in Washington State was diagnosed with “mad cow disease,” according to faculty members in the LSU AgCenter.
Bovine spongiform encephalopathy (BSE), commonly called mad cow disease, is a form of encephalitis that causes degeneration of the central nervous system in cattle. The disease is identified by the presence of misshapen proteins called prions in the tissues of an infected animal's nervous system, such as the brain and spinal cord.
BSE isn't transmitted by animal-to-animal contact, according to Steve Nicholson, a veterinarian with the LSU AgCenter. Animals contract the disease by eating contaminated tissue from diseased animals. Animal feed often is amended with the addition of bone meal and other animal byproducts as sources of protein.
To prevent BSE from being transmitted to cattle, the U.S. Department of Agriculture already had banned the use of cattle byproducts in feed intended for cattle or other ruminant species in 1997 after widespread outbreaks of the disease were found in England during 1986-87.
In the case of animals destined for human consumption, the spinal cord is removed from the carcass during slaughter operations and before any meat is removed, according to Ken McMillin of the LSU AgCenter's Department of Animal Sciences. This procedure is checked by meat inspection personnel and keeps nervous system tissue from contact with the meat people eat.
Researchers have not found BSE prions in milk, blood, meat or connective tissue of infected animals. It has been found only in nerve tissue.
“There's no indication that prions are present in muscle tissue,” McMillin said. “Ground beef is made from muscles that are too tough for use as cuts, so there's no reason to think it is any less safe than steak.”
Experts say BSE is one of several other animal and human diseases called transmissible spongiform encephalopathies (TSEs), which are found worldwide.