堆肥中大肠菌群等粪便污染指标菌的残留状况调查

Investigation on Survival of Coliform Bacteria in Various Composts

从日本九州地区23处堆肥化设施采集了以牛粪、鸡粪、污泥和餐厨垃圾为原料的堆肥试样29个,调查了大肠菌群等粪便污染指标菌的残留状况。结果表明,使用DESO培养基有11个试样被检出大肠菌群,检出率达38%,菌数在102~106 cfu.g-1的范围。使用API 20E鉴定系统对4个试样中的21个分离纯化菌株进行了菌种鉴定,发现有大肠菌群属的Escherichia coli、Escherichiavulneris、Pantoea sp.和Buttiauxella agrestis,以及非大肠菌群属的Serratia marcescens等肠内细菌科细菌。采用血清凝集试验对5株E.coli的病原性检测结果均为阴性。进一步针对6处堆肥设施的堆肥发酵过程中大肠菌群的消长追踪发现,大肠菌群数从原料到成品出现了逐渐减少直至消失、暂时消失、未完全消失、完全未检出4种走势,显示即使堆肥发酵温度在60℃以上,大肠菌群也有可能通过交叉污染等途径残留在堆肥成品中。

Occurrence and survival of fecal-contamination indicator（coliform bacteria）in various compost samples collected from 23 com-posting facilities in Kyushu were investigated by using selective media.Coliform bacteria were detected on desoxycholate agar（DESO）from 11（38%）of 29 product samples（15 cow dung manures,4 poultry manures,2 biosolid composts and 8 food waste composts）at a range of 102 ~106 cfu.g-1 dry matter.From positive samples,21 isolates were purified.from which,species of coliform bacteria（E.coli,E.vulneria,Pan-toea sp.and Buttiauxella agrestis）were identified,other bacteria（Serratia marcescens）were also observed,suggesting that careful identifi-cation was necessary to avoid false positive counting.Isolates of E.coli were tested for slide aggregation with a set of antiserums against pathogenic E.coli serotypes and negative reaction was obtained for all the isolates tested.Fate of fecal-contamination indicators was followed during compost production at 6 compost facilities and 4 patterns were observed：（1）decreased and finally disappeared（,2）decreased,then re-growth occurred in products,（3）decreased to certain extent and remained in products（,4）not detected even from raw materials.These re-sults suggested that some coliform bacteria might survive during compost production even temperature reached to as high as 60 ℃.