Excessive levels of radioactive cesium were found in mushrooms grown in Japan's Yamanashi region, according to a government report. The mushrooms contained 150 becquerels per kilogram of cesium, exceeding the permitted level of 100 becquerels per kilogram for general food products in Japan. The mushrooms were not distributed in the market and the Ministry of Health, Labor and Welfare regularly tests for radioactive substances in food after the Fukushima nuclear power plant incident.