Microbial contamination of fresh produce has emerged as a critical food safety challenge, as global consumption of raw and minimally processed fruits and vegetables continues to rise while conventional sanitizers show limited antimicrobial efficacy. Ozone has gained attention as a promising sanitizer due to its strong oxidizing properties and rapid decomposition into oxygen, leaving minimal harmful residues. However, its application in produce washing processes remains limited due to low solubility in water, high reactivity with organic matter, and slow gas-to-liquid transfer rates. Moreover, ozone’s instability and the need for on-site generation add operational complexity, while its efficacy can be reduced in the presence of high organic loads. To address these limitations, micro-nano bubble technology has been increasingly explored as a means to enhance ozone delivery and efficacy in washing processes. Micro-nano bubbles exhibit a high surface area-to-volume ratio, low buoyancy, and prolonged stability, which enhance mass transfer rates and gas utilization efficiency. While these characteristics facilitate more effective dispersion of ozone in water and prolong its oxidizing activity, the combination of micro-nano bubbles and ozone has not been systematically explored as a washing strategy for fresh produce. In particular, the effects of processing parameters on the physicochemical properties and antimicrobial efficacy of ozone micro-nano bubbles remain poorly understood. Additionally, the impact of ozone micro-nano bubble treatment on the quality and sensory attributes of fresh produce has not been well characterized. This dissertation aims to address these knowledge gaps through a series of interlinked studies. First, a meta-analysis was conducted to identify key processing parameters influencing the antimicrobial efficacy of ozone washing treatments. The results highlighted that sparging is the most effective method for microbial reduction, but also revealed gaps in the literature, including limited data on pH conditions and a lack of evaluations under dynamic and continuous systems that mimic industrial operations. Next, the influence of micro-nano bubbles on the antimicrobial efficacy of ozone-based washing was evaluated through comparison with conventional ozone water. The results demonstrated that micro-nano bubbles achieved higher microbial reduction compared to conventional ozone water, particularly after 10 minutes of treatment. The enhanced antimicrobial efficacy is attributed to the increased residual ozone concentration in micro-nano bubble water, resulting from reduced ozone decomposition and improved ozone stability. Given that fresh produce washing in industrial settings typically occurs within a short time frame of 1 to 5 minutes, the next study investigated strategies to improve microbial reduction within a 1-minute treatment time. In particular, the effect of solution pH was evaluated, as it can alter the ionic environment and thereby influence interactions between ozone micro-nano bubbles and bacterial cells. The findings showed that acidic conditions enhanced electrostatic interactions, leading to improved microbial inactivation within a 1-minute treatment time. Additionally, the study evaluated the effects of ozone micro-nano bubble treatment on post-wash quality and sensory attributes of romaine lettuce during storage to ensure the preservation of product quality. Finally, a novel bench-scale flume washer was developed to simulate industrial side-stream ozonation under laboratory conditions. The system incorporated rotating impellers and custom-designed 3D-printed cages to replicate produce movement through turbulent sanitizer flow while minimizing shear stress and maintaining consistent relative velocity between produce and fluid. Results demonstrated that the batch system achieved significantly higher microbial reduction than the continuous system without a side stream at an ozone concentration of 3 ppm. This was because ozone decomposed more rapidly in the continuous system due to enhanced mixing and turbulence caused by the rod rotation. Notably, by introducing a side-stream flow corresponding to 10% of the main flow rate, the continuous system achieved equivalent antimicrobial efficacy with only 1 ppm ozone concentration, compared to 3 ppm required in the batch system. This finding highlights the potential of ozone micro-nano bubble technology to improve antimicrobial efficacy while reducing ozone usage, thereby enhancing the sustainability of produce sanitation processes. Overall, this dissertation evaluated the impact of micro-nano bubbles on the efficiency of ozone-based washing processes for fresh produce to enhance microbial safety and maintain product quality during storage. The effects of processing conditions on antimicrobial efficacy were investigated in a batch system. To reflect industrial conditions, a bench-scale flume washer was developed to simulate side-stream ozonation under dynamic flow. Ozone micro-nano bubbles in this system achieved similar microbial reduction with lower ozone input, improving both process sustainability and safety by reducing ozone exposure. This research demonstrates the application of ozone micro-nano bubble technology as a practical, effective, and safer solution for fresh produce washing. These findings will advance the development of ozone-based washing processes and help bridge the gap between laboratory research and industrial application.