NEW : ` ` They 're not looking very hard for mad cow disease , '' a critic of USDA . South Korea is the second - largest importer of milk from the United States . The first U.S. case of mad cow disease in six years sparked fears of illness that prompted at least one major South Korean retailer to suspend the sale of American beef . In Korea , symptoms of mad cow disease include psychiatric and behavioral problems .
NEW : ` ` They 're not looking very hard for mad cow disease , '' a critic of USDA . South Korea is the second - largest importer of milk from the United States . In Korea , symptoms of mad cow disease include psychiatric and behavioral problems .