n general, isotopes of the same element behave similarly in terms of their physical properties and chemical reactivity (3). In addition, the distribution of radioactive 137Cs in rice grains is similar to that of stable 133Cs (4). Thus, the behavior of stable 133Cs is likely a useful indicator for predicting the behavior of radioactive Cs in sake brewing.Japan, a few food items had radioactive Cs levels in excess of 500 Bq/kg, which had been a provisional regulation value in Japan until March 2012.