Japan's radiation fears were renewed on Wednesday following news that contaminated beef from a farm just outside the Fukushima nuclear no-go zone has been shipped across the country and probably eaten.
Meat from 11 cows at the farm was found at the weekend to be contaminated with up to six times the legal limit of caesium and the farmer has since admitted he fed the animals straw exposed to radioactive fallout.
The readings of up to 3,200 becquerel per kilogramme were taken at a Tokyo meat-packaging plant, after earlier external readings at the farm had picked up no sign of radiation, according to officials.
The farm in Minamisoma, just beyond the 20-kilometre (12-mile) exclusion zone, had already sold six cows in May and June. Their beef was shipped across the country and much of it is believed to have been consumed.
Of the total amount, 1,438 kilogrammes (3,165 pounds) of beef were distributed to shops and restaurants in 12 prefectures, including Tokyo and Osaka, a Tokyo metropolitan government official said.
The government sought to reassure the public that there is no immediate threat. "Eating part of it in small amounts will not have a large impact on your health," said Goshi Hosono, minister in charge of the nuclear crisis.
Nonetheless, the case has stoked concerns about food safety, more than four months into the ongoing Fukushima nuclear crisis, after high readings have also been detected in some green vegetables, seafood and green tea.
Food testing remains largely under the control of prefectural officials, who admit that they can only carry out spot checks for contamination.
Fukushima prefecture officials said the farmer had stated in a questionnaire that the cows had not been fed contaminated straw, but tests later showed the straw contained caesium 56 times the legal limit, Kyodo News reported.