Persistence of Listeria and Salmonella During Swine Manure Treatment
Persistence of Listeria and Salmonella During Swine Manure Treatment
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DOI：
10.1080/1065657x.2007.10702311
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发表时间：
2007-01
影响因子：
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通讯作者：
S. Grewal;S. Sreevatsan;F. Michel
中科院分区：
文献类型：
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作者：
S. Grewal;S. Sreevatsan;F. Michel
众所周知，猪粪是多种人类和动物病原体的来源。特别值得关注的是引起人类食源性疾病的细菌，例如沙门氏菌和李斯特菌。常用的粪便处理对这些病原体持久性的影响很少进行比较。本研究的目的是比较最常用的粪便管理方法（液体储存、曝气液体储存、高温堆肥（55°C）和粪便包装（低温堆肥））处理猪粪过程中单增李斯特菌和鼠伤寒沙门氏菌的持久性。将来自俄亥俄州立大学农业技术研究所养猪场的猪粪接种单核细胞增生利斯特氏菌和鼠伤寒沙门氏菌，以获得每种生物体的终浓度为106 CFU/g。为了模拟液体储存，将粪便用水稀释并在 20-25°C 下充气和不充气储存。为了模拟包装储存和高温堆肥，用锯末修改相同的粪便以提供 60% 的水分，并分别在 25 和 55°C 的条件下在 3 个充气 4 升堆肥反应器中孵育。在第 0、3、7、14、28 和 56 天对处理进行取样，并使用标准方法分析李斯特菌和沙门氏菌的最可能数 (MPN)。在两种温度下，单增李斯特氏菌在所有处理中均可培养 28 天，并且在堆肥混合物中可培养至 56 天。 3 天后，55°C 堆肥和充气液体中单核细胞增生李斯特菌的 MPN/g 下降了 3 至 4 个对数，但 25°C 储存的堆肥或未充气液体中则没有。同样，3 天后，55°C 堆肥中的沙门氏菌 MPN 降至 44 MPN g−1，曝气液体中沙门氏菌 MPN 降至 1.2 × 104 MPN g−1，但 25°C 锯末粪肥混合物和未曝气液体中的沙门氏菌 MPN 没有变化。沙门氏菌在 55°C 的堆肥中可存活长达 28 天，在充气液体中可存活 42 天，在 25°C 堆肥和未充气液体中可存活长达 56 天。综上所述，结果表明，两种病原体在高温堆肥条件下被消灭得最快，并且它们在包装储存或低温堆肥条件下持续时间最长。然而，尽管在所有处理中，单核细胞增生李斯特氏菌在 14 天后下降了 4-5 个对数，但它在堆肥中持续保持低水平 (<1000 MPN g−1) 的时间比在液体厩肥处理中的时间更长。
Swine manures are known to be a source of a variety of human and animal pathogens. Of particular concern are bacteria causing human food-borne illnesses such as Salmonella and Listeria species. The effects of commonly used manure treatments on the persistence of these pathogens have rarely been compared. The objective of this study was to compare the persistence of Listeria monocytogenes and Salmonella typhimurium during the treatment of swine manure by the most commonly used manure management methods: liquid storage, aerated liquid storage, thermophilic composting (55°C) and manure packing (low temperature composting). Swine manure obtained from Ohio State University's Agricultural Technical Institute swine farm was inoculated with L. monocytogenes and S. typhimurium to obtain a final concentration of 106 CFU/g of each organism. To simulate liquid storage, manure was diluted with water and stored aerated and unaerated at 20-25°C. To simulate pack storage and thermophilic composting, the same manure was amended with sawdust to provide 60% moisture and incubated in triplicate aerated 4-liter compost reactors at 25 and 55°C, respectively. The treatments were sampled on days 0, 3, 7, 14, 28 and 56 and analyzed for the most probable numbers (MPN) of Listera and Salmonella using standard methods. L. monocytogenes was culturable in all the treatments for 28 days and in compost mixes through day 56 at both temperatures. The MPN/g of L. monocytogenes in the 55°C compost and the aerated liquid declined by 3 to 4 logs after 3 days, but not in the compost stored at 25°C or the unaerated liquid. Likewise after 3 days, Salmonella MPNs dropped to 44 MPN g−1 in the 55°C compost and 1.2 × 104 MPN g−1 in the aerated liquid but were unchanged in the sawdust manure mix at 25°C and the unaerated liquid. Salmonella persisted for up to 28 days in compost at 55°C, 42 days in aerated liquid and up to 56 days in both compost at 25°C and the unaerated liquid. Taken together, the results indicate that both pathogens were destroyed most rapidly under thermophilic composting conditions and that they persisted the longest in pack storage or low temperature composting conditions. However, although L. monocytogenes declined by 4-5 logs after 14 days in all treatments, it persisted at low levels (<1000 MPN g−1) longer in composts than in liquid manure treatments.