Cereal Chem 48:140 - 149.  |  VIEW ARTICLE
Effect of Storage Studies of Microorganisms on Gamma-Irradiated Rice.

H. Ito, S. Shibabe, and H. Iizuka. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

To observe the effect of storage at 30 C. on microorganisms on rice irradiated by gamma-ray, unpolished and polished rice harvested in Japan were used as samples. The storage life of polyethylene-packaged rice containing 14 to 15% moisture was extended 3 to 4 times by means of 0.2 Mrad irradiation. The number of molds on the irradiated rice grains was not increased for 3 to 4 months under these conditions. When the moisture in the rice sample was 17%, irradiation of more than 0.4 Mrad was necessary to extend its storage life. The only species of molds which can grow on storage-rice grains containing 14 to 15% moisture was Aspergillus restrictus. When moisture content was 16%, A. glaucus group and A. restrictus were observed. At 17% moisture, growths of molds were mainly members of A. glaucus group and Penicillium citrinum series, whereas A. restrictus, A. versicolor, etc. were minor ones. When a sheet of porous material, e.g., kraft-paper bag, was used to pack rice, the storge life of rice containing moisture of less than 15% was extended 3 to 4 times by means of 0.2 Mrad irradiation, the storage condition being 30 C., 75% r.h. In this case, the number of molds on rice was not increased for 3 to 4 months.