Abstract

Foodborne pathogens are a burden to the economy and a constant threat to public health. The ability to rapidly detect the presence of foodborne pathogens is a vital component of any strategy towards establishing a safe and secure food supply chain. Bacteriophages (phages) are viruses capable of infecting and replicating within bacteria in a strain-specific manner. The ubiquitous and selective nature of phages makes them ideal for the detection and biocontrol of bacteria. Therefore, the objective of this research was to develop and test a phage-based paper dipstick biosensor for the detection of various foodborne pathogens in food matrices. The first step was to identify the best method for immobilizing phages on paper such that their biological activity (infectivity) was preserved. It was found that piezoelectric inkjet printing resulted in lower loss of phage infectivity when compared with other printing methods (namely gravure and blade coating) and that ColorLok paper was ideally suited to create functional sensors. The phage-based bioactive papers developed with use of piezoelectric inkjet printing actively lysed their target bacteria and retained this antibacterial activity for up to 1 week when stored at room temperature and 80% relative humidity. These bioactive paper strips in combination with quantitative real-time PCR were used for quantitative determination of target bacteria in broth and food matrices. A phage dipstick was used to capture and infect Escherichia coli O157:H7, E. coli O45:H2, and Salmonella Newport in spinach, ground beef and chicken homogenates, respectively, and quantitative real-time PCR was used to detect the progeny phages. A detection limit of 10–50 colony-forming units per millilitre was demonstrated with a total assay time of 8 h, which was the duration of a typical work shift in an industrial setting. This detection method is rapid and cost-effective, and may potentially be applied to a broad range of bacterial foodborne pathogens.

Graphical abstract

摘要

食源性病原体是经济的负担，也是对公共健康的持续威胁。快速检测食源性病原体的存在的能力是建立安全可靠食品供应链的任何战略的重要组成部分。噬菌体（噬菌体）是能够以菌株特异性方式在细菌内感染和复制的病毒。噬菌体的普遍性和选择性使其成为细菌检测和生物控制的理想选择。因此，本研究的目的是开发和测试一种用于检测食品基质中各种食源性病原体的基于噬菌体的纸浸量尺生物传感器。第一步是确定将噬菌体固定在纸上的最佳方法，以便保留其生物学活性（传染性）。已经发现，与其他印刷方法（即凹版印刷和刮刀涂布）相比，压电喷墨印刷导致噬菌体感染性的损失更低，并且ColorLok纸非常适合创建功能传感器。当在室温和80％相对湿度下存储时，使用压电喷墨印刷技术开发的基于噬菌体的生物活性纸可主动裂解其目标细菌，并保持这种抗菌活性长达1周。这些生物活性纸条与定量实时PCR结合用于定量测定肉汤和食品基质中的目标细菌。噬菌体试纸用于捕获和感染 当在室温和80％相对湿度下存储时，使用压电喷墨印刷技术开发的基于噬菌体的生物活性纸可主动裂解其目标细菌，并保持这种抗菌活性长达1周。这些生物活性纸条与定量实时PCR结合用于定量测定肉汤和食品基质中的目标细菌。噬菌体试纸用于捕获和感染 当在室温和80％相对湿度下存储时，使用压电喷墨印刷技术开发的基于噬菌体的生物活性纸可主动裂解其目标细菌，并保持这种抗菌活性长达1周。这些生物活性纸条与定量实时PCR结合用于定量测定肉汤和食品基质中的目标细菌。噬菌体试纸用于捕获和感染菠菜，碎牛肉和鸡肉匀浆中的大肠杆菌O157：H7，大肠杆菌O45：H2和沙门氏菌Newport，并使用定量实时PCR检测子代噬菌体。检出限为每毫升10-50个菌落形成单位，总检测时间为8小时，这是工业环境中典型工作班次的持续时间。这种检测方法快速且具有成本效益，并且可能潜在地应用于广泛的细菌性食源性病原体。