Giner's Goal in this project is to address the USDA Topic Area 8.4, Conservation of Natural Resources, and subtopic 1 Water Quality and Quantity by developing a low-cost, field-portable, advanced molecular diagnostic device that enables rapid, on-site detection of low concentrations (1 CFU/100 mL) of E. coli O157 in environmental water samples without requiring specialized operator training and access to an advanced molecular testing laboratory. The availability of this sensor technology will vastly increase the adoption of reliable E. coli O157 testing in the horticultural industry, thus giving produce growers and regulatory authority stakeholders an important tool to rapidly monitor the microbiological quality of agricultural water and reduce the burden of E. coli disease outbreaks associated with fresh produce consumption.The overall goal of Phase I is to develop an electrochemical sensor for detection of E. coli O157 in environmental water used for irrigation of fresh produce farms. To accomplish this goal, we propose the following three (3) technical objectives:Objective 1. Amplify E. coli O157 Gene Biomarker in Water Samples Using SPAAC Ligation Reactions.Objective 2. Demonstrate Electrochemical Detection of Amplified E. coli O157 Gene Biomarker.Objective 3. Validate Full Assay Combining Amplification and Electrochemical Detection in Irrigation Water Samples Spiked with Cultured E. coli O157 Bacteria Cells.