Effects of atmospheric low-temperature plasma on blueberry quality and surface fungal diversity

Atmospheric pressure cold plasma (ACP) is an effective treatment method to kill microorganisms, which can protect food from microbial contamination, thereby maintaining the nutritional quality of food and extending the storage time of food. As a highly nutritious fruit, blueberries are susceptible to microbial contamination during the postharvest storage period. More seriously, the gray mold caused by Botrytis cinerea (B. cinerea) is a major postharvest disease of blueberries. Herein, this study investigated the effects of ACP treatment with different time (0, 5, 10, 15 and 20 min) on the natural decay, gray mold decay caused by B. cinerea, postharvest quality and the microbiota community composition and diversity of blueberries (Vaccinium corymbosum L.) during 10-d storage at 25 ± 2 °C. The results showed that ACP treatment inhibited the native microbial growth and natural decay of blueberries during the storage period. Meanwhile, ACP treatment also exhibited marked inhibitory effects on the spore germination and mycelial growth of B. cinerea in vitro, and gray mold decay in blueberries inoculated with B. cinerea during the postharvest storage. In terms of post-harvest quality, short-term (≤ 15 min) ACP treatment has little effect on firmness, pH, redox potential and anthocyanin content, but darkens the color of blueberries, reduces lipid peroxidation, and improves overall postharvest quality. However, the 20-min ACP treatment caused serious oxidative damage to the blueberry peels, resulting in softening of the fruit and decreased anthocyanin content. Moreover, the long-term low temperature storage reduced the abundance and diversity of fungal microorganisms on the surface of blueberries. Taken together, these results have important theoretical significance and practical value in revealing the mechanism of ACP on food preservation, improving the interaction between plasma and surface microorganisms of blueberries.