The Tokyo metropolitan government has ordered that beef from 11 cows from a farm in Fukushima Prefecture be removed from distribution because of radioactive contamination.
The meat has been found contaminated with cesium.
The animals came from a farm in Minami Soma, about 20 kilometers from the troubled Fukushima Daiichi nuclear power plant.
In a test, officials found Friday the beef from one of the cows contained 2,300 becquerels of cesium per kilogram.
The amount exceeded the legal limit by 500 becquerels per kilogram.
The meat from 10 other cows had between 1,530 and 3,200 becquerels of cesium per kilogram.
The same producer shipped 6 cows to Tokyo in May and June which were processed in a slaughter house without being tested for radioactive substances. The meat is believed to have already been distributed on the market.