STUDIES ON THE MICROORGANISMS FOUND IN THAI RICE AND BURMA RICE

PART 1. ON THE MICROFLORA OF THAI RICE

抄録

In investigating the causes of deterioration of cereal grains under the influences from microorganisms, the author has been of the opinion that the most important approach is to trace the movements of microflora in an ecological system termed cereal grains. This microbiological studies on the cause of the deteriorated rice, have been carried out in the same light. The results of this investigation are summarized as follows.
(1) The significant change of microflora after the normal maturity, would take place from immediately after to some time after polishing. In the freshly-polished new rice kernel after removing husks (inner- and outer-glume), bran layer (pericarp, endosperm, ) and sometime a part of aleuron layer, the microorganisms show significant decrease in number and Yellow Pseudomonas and some moulds known to invade rice during cultivation, such as Alternaria, Curvularia, Helmintosporium, Cepharosporium, etc. are found still remaining. However, soon after the polished rice is put in storage, the number of these microorganisms rapidly increase and instead come moulds such as White Aspergillus, bacteria such as Bacillus megatherium and Streptomyces begin to predominate.
(2) In normal rice which passed the wet season in storage from of polished rice, fairly many moulds such as Aspergillus mostly consisting of White Aspergillus and Penicillium are found and not much change is seen in bacteria in which Bacillus megatherium still predominates. But, it is a noteworthy fact that particularly many Streptomyces such as Streptomyces diastaticus, etc. are found in this specimen.
(3) In the polished rice after passing the wet season in storage, there is some rice of which deterioration can be recognized by visual inspection, for example FESCO standard. The common feature of these deteriorated rice is that Aspergillus, Penicillium and Streptomyces are found to be considerably more than in the normal rice. Therefore, deterioration of rice caused by microorganisms is considered to take place in Thailand depending upon the extent of increase of Aspergillus, Penicillium and Streptomyces during the storage period of polished rice.
(4) No attention has been paid to Streptomyces found in rice up to the present day. But, many of these were found not only in almost every specimen of normal polished rice but also in freshly-polished rice from the unhusked rice after one years storage. And these Streptomyces of rice mainly consist of Streptomyces diastaticus like strains. And it was found that some of these gaves considerably poisonous function when mice were fed with food containing rice with the strain grown on it.