The cultivation method of the mold strain described in the title and the results of its toxicological examinations are presented.
The Cultivation Method Observed: Each culture flask of 300ml in volume is filled with hulled rice immersed in tap water to two third of its volume after remaining water was thoroughly removed. The hulled rice as culture medium iss terilized in the cotton-stopered flasks for 15 minutes at 101b/inin². Subsequently, the mold seed is inoculated and the flasks are kept in an incubator at 30°C for 5 days and as a result of this procedure mold vigorously grows. The flasks are kept for further 14 days in a chamber maintained at 20°C to 23°C. The yellowed rice obtained is dried at 55°C to 60°C and ground.
Toxicological Testings of the Yellowed Rice: The diet containing the yellowed rice flour at the rate of 50 to 10% were subjected to the animal examination using mice fed with the test diet per os ad libitum.
Observation Results of Survival Lengtk of the Test Animals and Further Histological Study: The diet containing the yellowed rice flour at 50%, killed the test animals within 25 days and 25% diet within one month. About two third of all the test animals fed with 10% diet were observed to die within 300 days, the rests still surviving even after 400 days. Pathological findings regarding the test animals above described are as follows: In acute cases, fatty degeneration of the liver and round cell infiltration at periportal spaces in the slight degree were observed. Pleomorthism of the nuclei, without necrotic foci, was showed. In chronical cases, the round cell infiltration of periportal spaces was found to be remarkable and subsequently the infiltration was observed to extend to the central part of the liver. Swelling, hyperplasia of the liver cells and remarkable pleomorthism of the nuclei as well as hyperplasia of intrahepatic bile canaliculi were observed.