Effects of Curcumin-mediated Photodynamic Technology on Bactericidal Efficacy of Fresh-cut Potatoes

Photodynamic technology(PDT)was used as a kind of non-thermal sterilization in the research to sterilize fresh-cut potatoes. Curcumin was used as photosensitizer in all experiments and the excitation light source is a kind of blue light generated by the light emitting diode(LED),and the wave length was 420 nm in the experiments. In order to determine the optimal bactericidal conditions of PDT against Escherichia coli(E. coli)and Staphylococcus aureus(S. aureus)on the surface of fresh-cut potato slices,the bactericidal effects of different light power,light time,incubation time and photosensitizer concentration were detected by counting the number of E. coli and S. aureus after experiments. Results showed that the optimal sterilization conditions against E. coli on the surface of fresh-cut potato slices were:The light power was 40 W,the light time was 20 min,the incubation time was 15 min,and the concentration of curcumin was 30 μmol/L;the optimal sterilization conditions against S. aureus were:The light power was 20 W,the light time was 10 min,the incubation time was 15 min,and the concentration of curcumin was 30 μmol/L. Compared with the control group,the total number of bacterial colonies of E. coli and S. aureus after being treated by PDT were reduced by 3.60 and 5.23 lg CFU/mL,respectively.