More than a dozen regional governments in Japan will conduct tests to determine whether locally grown rice contains too much radioactive caesium, farm ministry officials said Monday, as food safety worries spill into the country's traditional staple. Public fears over radiation in food have grown after the world's worst nuclear crisis in 25 years at Fukushima plant in northeast Japan, and excessive levels of radiation have been found in beef, vegetables, tea, milk, seafood and water. The government Monday ordered Iwate prefecture in northern Japan to halt shipments of beef cattle after radiation exceeding safety standards was found in some Iwate beef, expanding the target of shipment ban from Fukushima and Miyagi. For rice, at least 14 prefectural governments in north and east Japan, which account for more than 40 percent of the country's total rice output, will test their rice before their harvest season to determine whether levels of caesium exceeds the safety standards, a farm ministry official said. If the level of caesium in rice exceeds the government-imposed cap of 500 becquerels per kilogram, shipments from locally produced rice will be halted, the official added. “Continuous consumption of rice containing caesium above the government-imposed limit of 500 becquerels per kg over a year will result in internal radiation exposure above 5 millisieverts, one of the more conservative standards for radiation exposure set by the International Commission on Radiological Protection,” said the Japanese health ministry. One becquerel means the activity of a quantity of radioactive material in which one nucleus decays per second. Japan, which produced about 8.3 million tonnes of rice last year for food consumption, mostly consumes its own produce, though it exported some 1,900 tonnes last year to countries including Hong Kong, Singapore and Taiwan. Chiba prefecture, north of Tokyo which has an early harvest deadline, plans to carry out its tests in the next two days, said Shigetoshi Abe, a Chiba prefectural government official, adding the central government's response has been too slow.