Hoang Hoang A, Nhung Nguyen T T
Department of Biotechnology, Faculty of Chemical Engineering, Ho Chi Minh City University of Technology, VNU-HCM, 268 Ly Thuong Kiet, District 10, Ho Chi Minh city, Vietnam.
Food Saf (Tokyo). 2018 Dec 21;6(4):143-150. doi: 10.14252/foodsafetyfscj.2018010. eCollection 2018 Dec.
In this study, a method using a recombinant phage for detection of O157:H7 in fresh vegetables was investigated. Four kinds of fresh vegetables, i.e. lettuce (), mustard greens (), coriander (), and soybean sprouts were selected since they are commonly used in meals in Vietnam. Firstly, a phage-based method was investigated for detection of O157:H7 in the four types of vegetables. To support the detection by suppressing growth of background bacteria in vegetables, selective antibiotics, i.e. novobiocin (N) and vancomycin (V) in combination with BHI medium were examined. Secondly, quality of the method was evaluated in terms of sensitivity, specificity, and rapidity. The method enabled the detection of O157:H7 inoculated at 10, 10, or 10 CFU/ 10 mL of sterile 0.8% NaCl containing 5 g of vegetable and in the presence of several Gram-positive and Gram-negative bacteria inoculated at 10 CFU/10 mL. The time for detection was approximately 16.5 hours for O157:H7 inoculated at 10 CFU/10 mL of sterile 0.8% NaCl containing 5 g of vegetable. The limit of detection was considered to be 2 CFU g vegetable.
在本研究中，对一种使用重组噬菌体检测新鲜蔬菜中O157:H7的方法进行了研究。选择了四种新鲜蔬菜，即生菜（）、芥菜（）、香菜（）和豆芽，因为它们在越南的饮食中常用。首先，研究了一种基于噬菌体的方法用于检测这四种蔬菜中的O157:H7。为了通过抑制蔬菜中背景细菌的生长来支持检测，研究了将新霉素（N）和万古霉素（V）与脑心浸液培养基联合使用的选择性抗生素。其次，从灵敏度、特异性和快速性方面评估了该方法的质量。该方法能够检测接种在含有5克蔬菜的10、10或10 CFU/10 mL无菌0.8%氯化钠中的O157:H7，以及接种在10 CFU/10 mL的几种革兰氏阳性和革兰氏阴性细菌存在的情况下的O157:H7。对于接种在含有5克蔬菜的10 CFU/10 mL无菌0.8%氯化钠中的O157:H7，检测时间约为16.5小时。检测限被认为是2 CFU/克蔬菜。
