Wisuthiphaet Nicharee, Yang Xu, Young Glenn M, Nitin Nitin
Department of Food Science and Technology, University of California, Davis, CA, USA.
Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA.
AMB Express. 2019 Apr 19;9(1):55. doi: 10.1186/s13568-019-0776-7.
Foodborne illness due to bacterial contamination is a significant issue impacting public health that demands new technology which is practical to implement by food industry. Detection of bacteria in food products and production facilities is a crucial strategy supporting food safety assessments. Bacteriophages were investigated as a tool for bacterial detection due to their ability to infect specific strain of host bacteria in order to improve sensitivity, specificity, and rapidity of bacterial detection. The results of this investigation reveal a novel method for rapid detection. The method employs a genetically engineered bacteriophage, phage T7-ALP, which expresses alkaline phosphatase. Upon infection of Escherichia coli, overexpression of alkaline phosphatase provides an opportunity for rapid sensitive detection of a signal indicative of bacterial presence in model beverage samples as low as 100 bacteria per gram. The method employs a fluorescent precipitated substrate, ELF-97, as a substrate for alkaline phosphatase activity coupled with fluorescence imaging and image analysis allowing single-cell imaging results in high detection sensitivity. The method is easily completed within less than 6 h enabling it to be deployed within most large industrial food processing facilities that have routine 8-h operational shifts.
由细菌污染引起的食源性疾病是一个影响公众健康的重大问题，需要食品行业能够实际应用的新技术。在食品和生产设施中检测细菌是支持食品安全评估的关键策略。噬菌体因其能够感染特定宿主细菌菌株的能力而被研究作为细菌检测工具，以提高细菌检测的灵敏度、特异性和快速性。这项研究的结果揭示了一种快速检测的新方法。该方法使用一种表达碱性磷酸酶的基因工程噬菌体T7-ALP。感染大肠杆菌后，碱性磷酸酶的过表达为在每克低至100个细菌的模型饮料样品中快速灵敏地检测指示细菌存在的信号提供了机会。该方法使用荧光沉淀底物ELF-97作为碱性磷酸酶活性的底物，结合荧光成像和图像分析，实现单细胞成像，检测灵敏度高。该方法在不到6小时内即可轻松完成，使其能够在大多数常规8小时轮班运营的大型工业食品加工设施中应用。
