University of Veterinary Medicine Hannover, Institute of Food Quality and Food Safety, Bischofsholer Damm 15, 30173 Hannover, Germany.
J Virol Methods. 2010 Oct;169(1):22-7. doi: 10.1016/j.jviromet.2010.06.008. Epub 2010 Jun 25.
Noroviruses are important causes of gastroenteritis; however, due to a lack of sensitive detection methods, the distinct role of contaminated food in norovirus outbreaks remains unclear. Two published virus extraction procedures combined with real-time RT-PCR for the detection of norovirus from food inoculated experimentally were compared. The elution-precipitation method was most efficient in all food matrices tested showing detection limits of 20 RT-PCRU for lettuce and ham, and 200 RT-PCRU for raspberries. The average recovery rates were 23%, 7% and 24% for lettuce, raspberries and ham, respectively. The ultrafiltration method yielded detection limits of 200 RT-PCRU for lettuce and ham, and 2000 RT-PCRU for raspberries; recovery rates were 9%, 7%, 3%, respectively. Subsequently, food items implicated in a norovirus outbreak were examined by the elution-precipitation method. Virus recovery rates determined by using MS2 phage ranged from 1 to 20% depending on the food matrix. However, norovirus could not be detected in the food items examined. This negative result may be explained by a low virus titer and heterogeneous virus distribution, or by random selection of food samples that contained no norovirus. Both, proper sampling and virus extraction from foods may be improved further to identify vehicles of infection.
诺如病毒是引起肠胃炎的重要原因；然而，由于缺乏敏感的检测方法，受污染食物在诺如病毒爆发中的明确作用仍不清楚。本文比较了两种已发表的病毒提取程序与实时 RT-PCR 联合检测经实验接种食物中诺如病毒的效果。在所有测试的食物基质中，洗脱沉淀法的效率最高，生菜和火腿的检测限为 20 RT-PCRU，树莓为 200 RT-PCRU。生菜、树莓和火腿的平均回收率分别为 23%、7%和 24%。超滤法的检测限为生菜和火腿 200 RT-PCRU，树莓 2000 RT-PCRU；回收率分别为 9%、7%、3%。随后，用洗脱沉淀法检测了与诺如病毒爆发有关的食物。使用 MS2 噬菌体确定的病毒回收率取决于食物基质，范围为 1%至 20%。然而，在检测的食物中未检测到诺如病毒。这种阴性结果可能是由于病毒滴度低和病毒分布不均，或者是由于随机选择的食物样本中不含诺如病毒。从食物中适当取样和提取病毒可以进一步改进，以确定感染媒介。
Zotero 插件