Occurrence of generic Escherichia coli, E. coli O157 and Salmonella spp. in water and sediment from leafy green produce farms and streams on the Central California coast
Occurrence of generic Escherichia coli, E. coli O157 and Salmonella spp. in water and sediment from leafy green produce farms and streams on the Central California coast
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DOI：
10.1016/j.ijfoodmicro.2013.04.003
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发表时间：
2013-07-01
影响因子：
5.4
通讯作者：
Mandrell, Robert E.
中科院分区：
文献类型：
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作者：
Benjamin, Lisa;Atwill, Edward R.;Mandrell, Robert E.
使用微生物质量较差的水进行灌溉会增加农产品中的细菌水平。本研究旨在确定与绿叶蔬菜农场灌溉水中的普通大肠杆菌相关的气候和管理变量，并测量大肠杆菌 0157 和沙门氏菌的流行率。这些农场的灌溉和非灌溉水源。 2008 年 5 月 27 日至 2010 年 10 月 26 日期间，从灌溉系统沿线的各个点以及从加州中部海岸农场的溪流和池塘收集的水和沉积物样品进行了培养，以检测普通大肠杆菌（MPN/100 mL 或 cfu 100 g）（n = 436）、大肠杆菌 0157（n = 437）和（n = 163）沙门氏菌。变量基于种植者的管理实践、样本附近的景观特征（例如，到道路和牧场/牲畜的距离）以及从在线数据库访问的气候数据。构建负二项式回归模型来测试农场水中的普通大肠杆菌 (MPN/100 mL) 与变量之间的关联。水中大肠杆菌的算术平均浓度（不包括摩尔拭子和沉积物样品中的浓度）分别为 7.1 x 10(2) MPN/100 mL 和 1.0 x 10(4) cfu/100 g。与收集日相匹配，沉积物中的大肠杆菌浓度 (cfu/100 g) 通常比这些灌溉系统的上覆水 (MPN/100 mL) 高 10 至 1000 倍。风速每增加 1 m/s，一般大肠杆菌浓度 (MPN/100 mL) 就会增加 60.1%；样本位置与牧场之间的距离每增加 10 m，就会减少 3%。与抓样样本 (1.8%) 相比，摩尔拭子检测到的水样中大肠杆菌 0157 阳性的比例 (13.8%) 更高； 1.7% 的沉积物样本可检测到这种病原体。有趣的是，季节与农产品农场或公共水源的水或沉积物中大肠杆菌 0157 的存在没有显着相关性。在 6% (6/96) 的水和 43% (3/67) 的沉积物样品中检测到沙门氏菌。普通大肠杆菌浓度与水或沉积物样品中大肠杆菌 0157 或沙门氏菌的存在没有显着相关性，这表明，在这 2.5 年期间和地理位置，普通大肠杆菌可能是预测关键农产品生产环境中这些食品和水源病原体存在的不可靠指示菌。 (C) 2013 Elsevier B.V. 保留所有权利。
Irrigation with water of poor microbiological quality can elevate levels of bacteria on produce. This study aimed to identify climate and management variables associated with generic Escherichia coli in irrigation water on leafy green produce farms and to measure the prevalence of E. colt 0157 and Salmonella spp. in irrigation and non-irrigation water sources on these farms. Water and sediment samples collected from various points along irrigation systems, as well as from streams and ponds on farms on the Central California coast between May 27th, 2008 and October 26th, 2010 were cultured for generic E. colt (MPN/100 mL or cfu 100 g) (n = 436), E. coli 0157 (n = 437), and (n = 163) Salmonella. Variables were based on grower's management practices, landscape features in proximity to samples (e.g., distance to roads and ranches/livestock), and climate data accessed from an online database. Negative binomial regression models were constructed to test associations between generic E. coli (MPN/100 mL) in water from farms and variables. Arithmetic mean concentration of E. coli for water, not including those from Moore swabs, and sediment samples, was 7.1 x 10(2) MPN/100 mL and 1.0 x 10(4) cfu/100 g, respectively. Matched by collection day, E. coli concentration in sediment (cfu/100 g) was typically 10- to 1000-fold higher than the overlying water (MPN/100 mL) for these irrigation systems. Generic E. coli concentration (MPN/100 mL) increased by 60.1% for each 1 m/s increase in wind speed and decreased by 3% for each 10 m increase in the distance between the sample location and rangeland. Moore swabs detected a higher proportion of E. coli 0157 (13.8%) positive water samples compared to grab samples (1.8%); 1.7% of sediment samples had detectable levels of this pathogen. Interestingly, season was not significantly associated with E. coli 0157 presence in water or sediments from produce farms or water sources with public access. Salmonella was detected in 6% (6/96) water and 43% (3/67) sediment samples. Generic E. coli concentration was not significantly associated with the presence of either E. coli 0157 or Salmonella in water or sediment samples, suggesting that, for this 2.5-year period and geographical location, generic E. coli would likely be an unreliable indicator bacteria for predicting the presence of these food- and waterborne pathogens in a key produce production environment. (C) 2013 Elsevier B.V. All rights reserved.