Japan suspects imported U.S. beef may have contained material considered at risk for mad cow infection, Japan's agriculture minister said. Agriculture Minister Shoichi Nakagawa said there was the possibility that material from cattle backbone was included in beef imported from the United States.
"If it is true, then this goes against the terms of the agreement," Nakagawa told reporters. "A thorough investigation needs to be conducted."
If confirmed, the news could dent U.S. lawmakers' efforts to get Japan to relax one of the terms under which it partially lifted a two-year old ban on American beef imports.
The ban was imposed in December 2003 after the discovery of the first case of mad cow disease in the U.S. herd.
The agreement allowed the import of meat only from cows aged 20 months or younger.
The deal excluded spines, brains, bone marrow and other parts of the cow thought to be at particularly high risk of containing mad cow disease.
U.S. lawmakers have been pressing Japan to allow beef from cattle that has been slaughtered at up to 30 months of age, as called for under international animal health guidelines.
But Nakagawa rejected those demands Wednesday, saying Japan could not accept such a change to the terms of the agreement.
Before the ban, Japan was the most lucrative overseas market for American beef, buying some US$1.4 billion worth in 2003.
Despite its return to local supermarket shelves and restaurant menus, U.S. beef still faces an uphill struggle in Japan, where consumers are particularly sensitive to safety concerns.
Mad cow disease is the common name for bovine spongiform encephalopathy, or BSE, a degenerative nerve disease in cattle that is linked to a rare but fatal nerve disorder in humans, variant Creutzfeldt-Jakob Disease.
Cows aged 20 months or younger so far have been free of the disease, reports the AP.