Polarized electric field induced by piezoelectric effect of ozone micro-nano bubbles/spontaneously polarized ceramic to boost ozonolysis for efficient fruit sterilization.

Ozone (O3) treatment is an environmentally friendly fruit sterilization strategy. However, the low O3 utilization rate and long-term oxidation lead to O3 waste and fruit damage, respectively. Herein, a sterilization system based on the synergy of O3 micro-nano bubbles (OMNB) and spontaneously polarized ceramic (SPC) was developed to piezoelectrically catalyze ozonolysis for efficient fruit sterilization. OMNB/SPC showed excellent sterilizing activity with 7 lg CFU/mL of E. coli and S. aureus inactivation within 20 min, together with significantly improved fruit quality in Kyoho grapes preservation. The excellent sterilizing performance of OMNB/SPC is attributed to that the piezoelectric SPC (d33 = 103.4 pm/V) formed a strong polarized electric field and rich reactive oxygen species (ROS) under OMNB collapse resulting in O3 absorption/decomposition. The electric field and rich ROS caused membranes in-situ electroporation and irreversible inactivation to the microorganisms on fruits successively. This system is important for more efficient long-term preservation of fruits.