The metropolitan government reported having found levels of radioactive cesium 4.6 times the national standard in cows raised in Minami-Soma, The Asahi Shimbun reported. Friday's discovery was the first time national standards have been exceeded in beef.
The contaminated cattle were raised on a ranch located within the zone in which people are subject to evacuate during emergencies related to the earthquake-tsunami disaster at the Fukushima No. 1 nuclear power plant, the newspaper said.
Government officials tested 10 cows after being processed at the Shibaura slaughterhouse, and all 10 had high levels of radioactive cesium. The Fukushima prefectural government asked the Minami-Soma local government to stop shipping or transporting cattle raised there.
All shipped cattle from Fukushima have their surfaces tested for radiation; the cattle in question were last tested June 26, and had shown no sign of radioactive materials, government officials said.