U.S Keeps Nervous Eye on Exports Amid Mad Cow Concerns

U.S. agriculture officials on Monday labored to convince foreign buyers of American beef that the meat is safe to consume, despite Friday's announcement of an "inconclusive" test for mad cow disease that caused volatile trading in Chicago futures markets.

U.S. Department of Agriculture (news - web sites) scientists in Ames, Iowa, were conducting more detailed lab tests on brain tissue samples from a suspect head of cattle. If those tests are negative for bovine spongiform encephalopathy, USDA could announce the results as early as Tuesday, according to one USDA official.

But a positive finding could prompt USDA to do additional testing, delaying any announcement, according to a meat industry source who asked not to be identified....