So far not a single person has died from eating an American cow infected with mad-cow disease (bovine spongiform encephalopathy). Nor has anyone even contracted Creutzfeldt-Jakob disease, the terrible brain-wasting illness, from eating parts of an infected American cow. The U.S. cattle industry slaughters 35 million cows a year.
But couldn't there be more mad cows out there that haven't been discovered? Sure, but even if you ate a steak made from them you are highly unlikely to get Creutzfeldt-Jakob disease. That's because the only part of the cow that passes on the disease to humans is the brain and spinal cord, which Americans generally don't eat. The outbreak of Creutzfeldt-Jakob tied to mad-cow disease in England probably came from meat pies containing these parts.
The disease doesn't occur in animals younger than 30 months, and most cows used for beef are slaughtered when they under 3 years old.
Since 1997, the U.S. Department of Agriculture has banned the use of "ruminant-derived feed," which could pass the disease to cows. And the Agriculture Department now tests about one in 90 cows for the disease.
If only to ease the public's fears, the Agriculture Department has decided to make changes in the testing system. Henceforth, when a rapid test the test commonly used in the United States comes up positive for an infected cow, it will be confirmed with two other tests considered the "gold standard" for assuring beef safety. They are the immunohistochemistry test and the Western blot test.
The Harvard Center for Risk Analysis has studied the risks of mad-cow disease in the United States and found them to be "very, very low," according to its director, George Gray. So go ahead and throw that burger on the grill, if you're so inclined.