The overall goal is to evaluate the existing and novel strategies and proposed regulations for mitigating irrigation-induced contamination of produce. The central hypothesis is that contamination of spinach and cantaloupes at harvest can be effectively reduced by improved irrigation management. This hypothesis will be addressed through the following objectives: (1) Conduct an intervention trial of effectiveness of two treatments of surface water for irrigation: the existing ultraviolet (UV) radiation treatment and a novel sulfuric acid-fertilizer (SA-fertilizer) based treatment compared to a no-treatment control, on the prevalence of produce contamination with Salmonella and prevalence and level of indicators at harvest. Trials will be conducted over two growing seasons in parallel for spinach and cantaloupes. Surface water naturally contaminated with Salmonella and spiked with a non-pathogenic surrogate generic Escherichia coli inoculum will be used for irrigation in both furrow and drip irrigation systems; (2) Determine irrigation-induced dissemination of pathogens and indicators and the rate of indicator die-off on spinach and cantaloupes with respect to the lag time between last irrigation and harvest. Data from the intervention trials will be evaluated using random effect models that control for the effect of additional factors: produce commodity (spinach vs. cantaloupes), water treatment (no-treatment vs. UV treatment vs. SA-fertilizer treatment), irrigation system (furrow vs. drip), time since planting, location within a field, contamination of soil and weather pattern; and (3) Develop Good Agricultural Practices for management of irrigation in a form of user-friendly decision trees.