The USDA's refusal to allow meat processors to do their own testing further undercuts the safety of U.S. beef, Law Review Editor Gregory Berlowitz wrote.

The Bush administration's approach has been to deny the problem and resist comprehensive testing for bovine spongiform encephalopathy, he said.

While a Japan-led 53-nation ban on U.S. beef prompted the United States to test half of so-called "downer" cows -- those that cannot walk -- Berlowitz noted that still is just 2 percent of the U.S. herd.

The USDA must adopt "a mix of mandatory and voluntary (producer) testing to ensure the largest possible number of cattle are tested, while working to open foreign markets for American beef on the basis of the reliability of that testing," Berlowitz wrote.

While Congress banned recycling dead cows and sheep into cattle feed in 1997, the Food and Drug Administration is "far behind" on inspections of the practice, believed to be still used widely, Berlowitz said.