Inactivation of E.coli in fresh fruit juice using dielectric barrier discharge plasma (DBDP)

Non-thermal pasteurization processes can offer higher quality, better nutrition retention and more energy efficient compared with traditional thermal processes. In this paper, dielectric barrier discharge reactor (DBDR) was designed. And the bactericidal efficiency of low-temperature plasma (LTP) produced by DBDR on fresh juice and its impacts on the quality of juice were researched. The second order quadratic equation for DBDR inactivation was established by response surface methodology, and the effectiveness of this model was verified. Also, effects of cycles, pH value, temperature and voltage on DBDP sterilization of E.coli were discussed. Based on the exploration, the optimum conditions for inactivation of E.coli ATCC 8739 of seven log cycles were obtained as: 6 cycles, pH 3.14, temperature 39.72°C, and voltage 21.42 kV. It lays a foundation for further studying on the DBDP sterilization law and the mechanism of sterilization. While the correlation coefficient R2 for this model equals to 0.9817, the low-temperature plasma (LTP) produced by DBDR can be applied to other fruit and vegetable disinfection treatment and improve the quality and safty of fresh fruit and vegetable.