Dynamics of Radioactive Cesium ( super( 134)Cs and super( 137)Cs) during the Milling of Contaminated Japanese Wheat Cultivars and during the Cooking of Udon Noodles Made from Wheat Flour

The fate of radioactive cesium ( super( 134)Cs plus super( 137)Cs) during the milling of contaminated Japanese wheat cultivars harvested in FY2011, and during the cooking of Japanese udon noodles made from the wheat flour, was investigated. Grain samples containing various radioactive cesium concentrations (36.6 to 772 Bq/kg [dryweight]) were milled using a laboratory-scale test mill to produce eight fractions: three break flours (1B, 2B, and 3B), three reduction flours (1M, 2M, and 3M), bran, and shorts. The concentrations of radioactive cesium were found to be highest in the bran fractions of all the samples tested, with 2.3- to 2.5-fold higher values than that of the whole grain. Shorts contained radioactive cesium levels similar to that of the whole grain. In contrast, radioactive cesium concentrations in other fractions were found to be less than half the concentration in whole grain. The average processing factor (PF) value calculated for patent flour (0.401 plus or minus 0.048), made from the mixture of 1B, 2B, 1M, and 2M for human consumption, or for low-grade flour (0.467 plus or minus 0.045), made from the mixture of 3B and 3M, was found to be less than 0.5; whereas the average PF value (2.07 plus or minus 0.232) for feed bran (mixture of bran and shorts), which has been used mainly as livestock feed in Japan, was over 2.0. Boiling udon noodles (made from patent flour) resulted in a substantial reduction (>70% of initial amount) of radioactive cesium. Moreover, radioactive cesium was reduced further (