Wang D, Huber A, Dunfield K, Murray K, Wu F, Warriner K
a Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada.
b Soil Research Group, Guelph, ON N1H 2Y5, Canada.
Can J Microbiol. 2018 Dec;64(12):979-991. doi: 10.1139/cjm-2018-0234. Epub 2018 Aug 27.
The fate of Salmonella and Escherichia coli O157:H7 in swine or dairy manure amended into sandy loam or loam soil under field conditions was studied. Soil was amended with manure inoculated with a Salmonella or E. coli O157:H7 cocktail, then transferred to 0.22 μm pore size membrane walled vials. The vials were then placed on the surface or at 15 cm depth in the test plots. Pathogen numbers, soil moisture, rainfall, and temperature were measured throughout the three trials (20-47 weeks duration) representing spring or fall application. Survival curves were characterized by having an initial rapid decline in pathogen numbers followed by a slower inactivation phase with an occasional increase in culturable cells. The CT values (time to reach a 3 log CFU reduction) varied from 2 to 120 days, with the most rapid decrease being observed on the surface of sandy loam soil. The persistence of pathogens is primarily governed by variations in moisture and temperature, although season of application along with manure and soil type also contribute. To generate more accurate predictive pathogen models, there is a need for laboratory-based trials to mirror the dynamic variation in temperature and soil moisture encountered within the natural environment.
研究了在田间条件下，添加到砂壤土或壤土中的猪粪或奶牛粪中沙门氏菌和大肠杆菌O157:H7的命运。用接种了沙门氏菌或大肠杆菌O157:H7混合菌液的粪便对土壤进行改良，然后转移到孔径为0.22μm的带膜壁小瓶中。接着将小瓶放置在试验地块的表面或15厘米深处。在代表春季或秋季施用的三个试验（持续20 - 47周）期间，对病原体数量、土壤湿度、降雨量和温度进行了测量。存活曲线的特征是病原体数量最初迅速下降，随后是一个较慢的失活阶段，可培养细胞偶尔会增加。CT值（达到3个对数CFU减少所需的时间）从2天到120天不等，在砂壤土表面观察到下降最快。病原体的持久性主要受湿度和温度变化的影响，尽管施用季节以及粪便和土壤类型也有作用。为了生成更准确的病原体预测模型，需要进行基于实验室的试验，以反映自然环境中遇到的温度和土壤湿度的动态变化。
