Abstract: Objective: This study was conducted to evaluate the fungicidal effect of low-temperature plasma generated by gas phase surface discharge on the spores of Penicillium expansum. Methods: Two strains (CICC 40658 and F-LPH10-06) of P. expansum were used to investigate their growth and patulin-producing characteristics in potato dextrose broth medium. Low-temperature plasma generated by gas phase surface discharge sterilizer was developed and used to study the effect of treatment time, power supply voltage and initial spore concentration on its fungicidal effect against P. expansum. Furthermore, the morphological changes of P. expansum spores were characterized using scanning electron microscopy (SEM). Results: The biomass (dry weight) of P. expansum CICC 40658 and F-LPH10-06 were 28.6 and 128.7 mg after 14 days of culture, respectively. The concentration of patulin produced by P. expansum F-LPH10-06 was 147.97 mg/L at the end of incubation, which was nearly 162 times higher than that produced by CICC 40658 (912.40 μg/L). CICC 40658 at an initial concentration of 3.4 × 106 spores/mL could be completely killed after 21 min treatment by low-temperature plasma generated by gas phase surface discharge. For F-LPH10-06 (1.5 × 106 spores/mL), a reduction of 4.58 lg(spores/mL) was observed after treatment for 30 min. In addition, the fungicidal effect was enhanced with the increase in discharge voltage or decrease in initial spore concentration after the same treatment time. SEM observation showed that the morphology of spores changed after treatment, which may be related to the charged particles with high energy and reactive oxygen species produced during high voltage discharge. Conclusion: Low-temperature plasma generated by gas phase surface discharge has strong fungicidal effect against P. expansum, which may provide an important theoretical basis for the development and application of low-temperature sterilization technology.

Key words: low-temperature plasma, gas phase surface discharge, Penicillium expansum, fungicidal effect, patulin DOI:10.7506/spkx1002-6630-201721001