Synergistic micro-nano bubble treatment via high-speed vortex and ultrasound enhances quality and safety of lettuce and cherry tomatoes.

This study aimed to address quality deterioration and microbial contamination in fresh produce during postharvest storage by exploring efficient and safe cleaning technologies. The effects of three micro-nano bubble (MNB) treatments generated via ultrasound (US), high-speed vortex (HV), and their synergistic system (HV-US) on the quality and safety of lettuce and cherry tomatoes were compared. Results showed that the HV-US synergistic system significantly outperformed the individual treatments (p < 0.05), which was attributed to its smaller bubble size, higher dissolved oxygen content, stronger oxidative capacity. HV-US significantly reduced weight loss rates (3.19% for lettuce and 3.59% for tomatoes), increased firmness (2.12 N and 5.61 N), and minimized color changes (ΔE⁎ of 22.0 and 7.8) during storage (p < 0.05). It also significantly inhibited polyphenol oxidase (PPO) and peroxidase (POD) activities, reduced vitamin C (Vc) degradation by 30% in lettuce and 22% in cherry tomatoes, decreased microbial counts by 2.09 and 2.90 log CFU·g-1, and lowered pesticide residues to 10.2 μg·kg-1 and 8.2 μg·kg-1, respectively (p < 0.05). These findings demonstrate that the HV-US synergistic MNB treatment effectively improves the cleaning efficiency, storage quality, and safety of fresh fruits and vegetables, showing high potential for postharvest industrial applications.