@article{oai:repository.naro.go.jp:00002277,
 author = {花島, 大 and HANAJIMA, Dai},
 journal = {畜産草地研究所研究報告, Bulletin of National Institute of Livestock and Grassland Science},
 month = {Mar},
 note = {Animal waste is utilized as an organic fertilizer after it is subjected to composting or the liquid composting process. Food security and safety are a great concern for consumers; therefore, effective treatments are required to ensure organic fertilizer hygiene. It is well known that proper composting effectively destroys pathogens in animal waste through the high temperature achieved by the process. In Japan, sawdust or rice straw is normally used as a bulking agent for moisture adjustment, though a constant supply of these bulking agents cannot be expected. In case of a shortage of bulking agents, composting with high moisture content materials such as cattle feces is inevitably carried out under inappropriate conditions. In this study, to ensure pathogen reduction during composting of cattle feces, I investigated co-composting with a variety of organic wastes. In addition, recently, the regrowth of pathogens in finished compost when appropriate temperature and moisture conditions are provided is becoming an issue, even though the pathogen population decreases to a low level during the composting process. Since the use of such compost which allows the pathogen regrowth is unfavorable, I evaluated the E. coli regrowth potential in various types of compost. There are few reports on the dynamics of pathogens and the mechanisms of their reduction during the liquid composting of animal waste. In this study, the relationship between the dynamics of the E. coli population and the biological and physiochemical factors that may affect E. coli survival was investigated. 　The results showed that the addition of organic wastes to high moisture content cattle feces significantly increased heat generation compared to the treatment wherein organic wastes were not added, and the maximum temperatures of more than 55℃ remarkably reduced the E. coli population. This temperature increase depends on the amount of easily digestible organic carbon present in organic wastes, and we observed a positive correlation between the maximum temperatures and the values of biochemical oxygen demand (BOD), an indicator of easily digestible organic carbon. Significant E. coli regrowth was observed in the compost samples collected during or immediately after the thermophilic phase. Therefore, the risk of regrowth is considered to be the highest in immature compost. During the liquid composting process, the E. coli population significantly decreased during the initial phase of the process. However, the E. coli reduction was not due to high temperatures; therefore, the mechanism for E. coli reduction is different between the solid and liquid composting processes. It is speculated that the reduction of the E. coli population may be due to the competition with Bacillus, which was found to be predominant during the E. coli decreasing phase, and/or the changes in physicochemical factors induced by the degradation of organic substances and the production of metabolites during the process. These results indicate that thermophilic and curing stages are important for E. coli elimination during solid composting. Further investigation is required for the elucidation of the mechanism for E. coli reduction during liquid composting process., 家畜排泄物は主として堆肥化, 液肥化を経て循環利用されているが, 食の安心・安全に対する消費者の関心は高く, 有機肥料の生産段階においてもこれまで以上に衛生的な処理が望まれている. 一般的に堆肥化過程で発生する高温は有害微生物の低減に効果があることが知られているが, 牛糞のような高水分堆肥原料の堆肥化に際し, オガクズや稲ワラ等の水分調整材の使用が十分でない場合には, 適正な堆肥化プロセスが進行しない事例も見受けられる. そこで本研究では, 温度が上昇しにくい高水分の堆肥原料中での有害微生物の低減化を促進させる方法として, 家畜糞と食品副産物等の有機廃棄物との混合堆肥化を検討した. また近年, 堆肥化過程で一度は低減した有害微生物が, 水分や温度など適当な生育条件が整うことで再増殖するという現象が問題となっている. 堆肥の安全性を考える上でこのような堆肥の流通は好ましくないことから, 再増殖を起こす可能性のある堆肥の類型化を行った. 液肥化処理についてはそもそも研究蓄積が少なく, 処理過程の有害微生物の動態や死滅機構は十分に明らかになっていない. そこで通気処理過程における糞便汚染指標微生物である大腸菌の消長についての知見を得るとともに, 大腸菌数の推移に影響を与えると予測される物理化学的, 生物的パラメータの推移を解析し, それらの関連性について検討を行った. 　その結果, 高水分牛糞に対する有機廃棄物の添加は, 無添加の原料に比べ大幅に温度上昇を促進し, 55℃を超える高温を維持することで, 大腸菌数を激減させることが明らかとなった. この温度上昇は主として添加廃棄物中の易分解性有機物量に依存し, 堆肥温度と易分解性有機物量の指標であるBOD（Biochemical Oxygen Demand）値の間には正の相関が認められた. また大腸菌の再増殖は, 高温期の, または高温期が終了直後の堆肥サンプルにおいて顕著に認められることから, 再増殖のリスクは有機物分解が十分に進行していない堆肥において特に高いことが明らかとなった. 液肥化過程において大腸菌は, 初期の段階で大幅に減少していた. 堆肥化とは異なりこの低減機構は温度によるものではなく, 大腸菌低減時に著しく優占する未培養のBacillus 属細菌など共存する微生物群との競合, または有機成分の分解と代謝産物の生成に起因する液中の物理化学的変化が大腸菌の生存に影響を及ぼしているものと考えられた. 以上から, 堆肥については高温処理の徹底, および十分な腐熟期間の保持が, 液肥については, 温度以外の生物的, 物理化学的要因による大腸菌低減のメカニズムの解明が衛生的な処理の確立に対して重要であると考えられた.},
 pages = {71--111},
 title = {家畜排泄物処理における大腸菌の制御に関する研究},
 volume = {9},
 year = {2009},
 yomi = {ハナジマ, ダイ}
}