Design of a continuous plasma activated water (PAW) disinfection system for fresh produce industry

This study introduces an innovative, industrial-scale continuous Plasma Activated Water (PAW) system, specifically designed for the fresh produce industry and optimized for micro to small enterprises. The system leverages a novel non-uniform electrode design to enhance average field strength, driving the efficient generation of reactive oxygen and nitrogen species (RONS) for steady-state PAW production. Key components include a venturi bubble generator for optimized gas-liquid interaction and a plasma reactor integrated with a continuous spray and drying setup, enabling consistent PAW production and application. Our preliminary results indicate about 1.5 log₁₀ CFU/g decrease in microbial load on treated produce, which further decreased to 2.5 log₁₀ CFU/g towards the end of storage life for tomatoes, with 20 kV applied to the reactors and a total residence time of 20 min. An evaluation of the maximum energy consumption of system indicated a process cost contribution of less than $0.5 per ton of treated produce. The promising initial results, scalable design, cost-effectiveness and sustainability aspects make this technology suitable for improving food safety while reducing chemical usage.