In investigating the causes of deterioration of cereal grains under the influences of microorganisms, the author has held the view that the most important approach is to trace the movements of microflora in an ecological heterogenous system, termed cereal grain. Such microbiological studies on the cause of deteriorated rice, have been carried out in the same light. Results of this investigation are summarized as follows.
(1) From a standpoint of microbiology, rice will be stored in unhusked form, which affords far more safety than in the polished form in Burma.
(2) In regard of the movements of microflora during the storage period of unhusked rice in Burma, new crop rice gives very few Aspergillus and Penicillium and many so-called Yellow Pseudomonas, i.e: Pseudomonas lacnogenes, P. perlurida, P. xanthe, P. myxogenes, etc. however, in normal rice after it is stored during raining season in the form of unhusked rice, the number of Aspergillus, i.e: white Aspergillus, A. versicolor, A, fumigatus, A. glaucus group, etc. Penicillium, i.e; P. citrinum, P. notatum, P. oxalicum, P. commune, P. cyclopium, P. islandcium, P. rugulosum, P. chrysogenum, etc. and Streptomyces increase.
(3) There is some rice of which deterioration can be recognized by visual inspection. The common feature of this deteriorated rice is that considerably more amounts of Aspergillus, Penicillium and Streptomyces are contained than in normal rice.
(4) Up to the present no attention has been paid to Streptomyces found in rice. However, from the author's investigations many of these were found in almost every specimen of normal rice. Furthermore, these Streptomyces of rice mainly consist of S. diastaticus, S. leben, Stessel and Keitt, S. carifornicus, S. albus, S. intermedium etc. It was further found that some of these Streptomyces possesses a considerably poisonous function when mice were fed with food containing rice with any one of these strains grown on.