In South Korea , one of the world 's largest importers of U.S. beef , the discovery of bovine spongiform encephalopathy led retailer LotteMart to remove American beef from store shelves . ` `` They 're not looking very hard for mad cow disease , '' says critic of USDA . Comment: In people , symptoms of mad cow disease include psychiatric and behavioral changes .
`` They 're not looking very hard for mad cow disease , '' says critic of USDA . Comment: In people , symptoms of mad cow disease include psychiatric and behavioral changes .