An Integrated Real-time Electrochemical LAMP Device for Pathogenic Bacteria Detection in Food

A novel, integrated, real-time electrochemical loop-mediated isothermal amplification (LAMP) device for pathogen detection in food was developed. The electrochemical LAMP device for detection of the vt gene in E. coli O157:H7 and invA gene in Salmonella enterica was implemented with DNA intercalating probes-methylene blue. To improve assay efficiency, the optimal concentration of MB was determined to be 30M. The real-time electrochemical LAMP results of gene serial dilutions were compared to the fluorescence-based detection method. For E. coli O157 and Salmonella, the assay detection limits were 10 DNA copies and 1 DNA copy, respectively, in a reaction time of less than 30min. The electrochemical and optical LAMP method analyses were realized with 10% milk to simulate the turbid environment of real food samples. In real-time LAMP of Salmonella in a turbid environment, the detection limit of 10 copies without pretreatment was possible using the electrochemical method only. Our electrochemical device was used for bacterial detection in 150 turbid food samples, including juice, milk, and soy milk. This electrochemical device has many advantages, including size, portability, high specificity, and high sensitivity, while also being a user-friendly device that provides stable signals. Thus, to the best of our knowledge, this new electrochemical device demonstrates the best performance for bacterial detection in the rapid contaminated food detection category.