The Agriculture, Forestry and Fisheries Ministry issued a report Monday stating there are no assurances that more cases of mad cow disease won't be discovered in the United States.
"There is no guarantee that mad cow disease will not occur in the U.S. from now," the report says.
The report was based on the findings of a team of Japanese experts who returned home Sunday after visiting the U.S. and Canada following the discovery last month of a Canadian-born cow in Washington state infected with mad cow disease, or bovine spongiform encephalopathy.