The U.S. Department of Agriculture Tuesday announced stricter measures to further ensure the safety of the American beef supply from mad cow disease, adding that American beef remains safe for domestic and international consumption.

U.S. Agriculture Secretary Ann Veneman announced a ban on the slaughter of sick, so-called "downer," cows like the one discovered last week with mad cow disease in Washington state.

Under the new restrictions, meat from the diseased cow would not have gotten into the food supply. Recalls for the beef were announced in eight U.S. states and Guam.

In addition, meatpackers will be barred from using the small intestines, head and spinal tissue from older cows, born prior to a rigorous inspection program for mad cow disease implemented in 1997, and packers will no longer be allowed to use certain slaughering techniques that might contaminate safe meat.

Secretary Veneman also announced the appointment of an international panel of scientists to review the U.S. response to mad cow disease. "Sound science continues to be our guide," she said.

Officials believe the contaminated cow in Washington state was one of 82 head from the same Canadian herd imported to the United States. Last May, a cow infected with Mad Cow disease was discovered in Alberta.

Intensive efforts are underway in the U.S. to trace the movement of the cows, and those that have been found are being quarantined for further testing.

Secretary Veneman again stressed the safety of American beef. "The risk of BSE spreading in the U.S. is extremely low," she said.

Mad Cow disease, also known as BSE (bovine spongiform encephalopathy), is a fatal, neurological disorder that cattle get by eating infected meal from other animals, such as sheep. Humans can contract a version of the disease from diseased cows.