Department of Veterinary Science and Microbiology, University of Arizona, Tucson, AZ 85721, USA.
J Appl Microbiol. 2012 Mar;112(3):485-92. doi: 10.1111/j.1365-2672.2011.05222.x. Epub 2012 Jan 17.
We investigated the antimicrobial effectiveness of lemongrass essential oil on organic leafy greens, romaine and iceberg lettuces and mature and baby spinach, inoculated with Salmonella Newport. The influences of exposure times and abuse temperatures on bacterial survival were also investigated.
Leaf samples were washed, inoculated with Salm. Newport (6-log CFUml(-1) ) and dried. Inoculated leaves were immersed in solutions containing 0·1, 0·3 or 0·5% lemongrass oil in phosphate-buffered saline for 1 or 2min and then individually incubated at 4 or 8°C. Samples were taken at day 0, 1 and 3 for the enumeration of survivors. Compared to the PBS control, romaine and iceberg lettuces, and mature and baby spinach samples showed between 0·6-1·5-log, 0·5-4·3-log, 0·5-2·5-log and 0·5-2·2-logCFUg(-1) reductions in Salm. Newport by day 3, respectively.
The antimicrobial activity of lemongrass oil against Salm. Newport was concentration and time dependent. The antimicrobial activity increased with exposure time; iceberg samples treated for 2min generally showed greater reductions (P<0·05) than those treated for 1min (c.1-log reduction difference for 0·3 and 0·5% treatments). Few samples showed a difference between refrigeration and abuse temperatures.
This study demonstrates the potential of lemongrass oil solutions to inactivate Salm. Newport on organic leafy greens.
我们研究了柠檬草精油对有机叶菜类、罗马生菜和卷心生菜以及成熟和婴儿菠菜的抗菌效果，这些蔬菜均接种了纽波特沙门氏菌。还研究了暴露时间和滥用温度对细菌存活的影响。
将叶片样本洗净、接种沙门氏菌纽波特（6 对数 CFUml(-1) ）并干燥。将接种后的叶片浸入含有 0.1%、0.3%或 0.5%柠檬草油的磷酸盐缓冲盐水溶液中 1 或 2 分钟，然后分别在 4°C 或 8°C 下孵育。在第 0、1 和 3 天取样以计数存活的细菌。与 PBS 对照组相比，罗马生菜和卷心生菜以及成熟和婴儿菠菜样本中，沙门氏菌纽波特的数量分别减少了 0.6-1.5 对数、0.5-4.3 对数、0.5-2.5 对数和 0.5-2.2-logCFUg(-1) ，在第 3 天。
柠檬草油对沙门氏菌纽波特的抗菌活性与浓度和时间有关。抗菌活性随暴露时间的增加而增加；2 分钟处理的冰菜样本通常比 1 分钟处理的样本（0.3%和 0.5%处理的情况下相差约 1 个对数）表现出更大的减少（P<0.05）。少数样本在冷藏和滥用温度之间没有差异。
本研究表明柠檬草油溶液有潜力使有机叶菜类蔬菜上的沙门氏菌纽波特失活。
