Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2021
Publication Date: 11/9/2021
Citation: Saito, S., Wang, F., Obenland, D.M., Xiao, C. 2021. Effects of peroxyacetic acid on postharvest diseases and quality of blueberries. Plant Disease. 105(10):3231-3237. https://doi.org/10.1094/PDIS-10-20-2310-RE.
Interpretive Summary: Postharvest diseases are a limiting factor for storage of fresh blueberries. Gray mold and Alternaria rot are important postharvest diseases in blueberries grown in California. Control of these fungal diseases is generally dependent on fungicide application. However, multiple fungicide resistance has been reported in those pathogens in California. To reduce the risk of development of fungicide resistance and maintain efficacy of fungicide application, alternative treatments are needed to control postharvest diseases of blueberries. Peroxyacetic acid (PAA) is a disinfectant agent and has been used for many fresh fruit and vegetables to control foodborne microorganisms. In this study, we evaluated the effects of PAA on the control of postharvest diseases and fruit quality. PAA was applied as a dip or in spray form in two different recommended concentrations to four cultivars over two seasons. Results showed that PAA treatment reduced postharvest diseases of blueberry, regardless of application methods, and did not affect fruit quality substantially. Because PAA is a safer than other disinfectant agents and eco-friendly, PAA treatment has the potential to be incorporated in a commercial sanitation process prior to blueberry packing.
Technical Abstract: Postharvest diseases are a limiting factor for storage of fresh blueberries. Gray mold caused by Botrytis spp. and Alternaria rot caused by Alternaria spp. are important postharvest diseases in blueberries grown in California. Control of these fungal pathogens is generally dependent on preharvest sprays of synthetic fungicides, but in California multiple fungicide resistance has been already detected in those pathogens. Therefore, alternatives to synthetic fungicides are needed for the control of postharvest diseases. Peroxyacetic acid (PAA) is a disinfectant agent that is generally recognized as safe (GRAS). In this study, we evaluated the effects of PAA at 24 µL L-1 and 85 µL L-1 on fruit decay caused by fungal pathogens and quality of stored blueberry fruit. PAA treatment was applied to four cultivars over two seasons using two methods, dipping or spray, to simulate different modes of packinghouse sanitation processing. Results showed that 85 µL L-1 PAA treatment significantly reduced the percentage of naturally occurring fruit decay as well as disease severity on fruit artificially inoculated with B. cinerea or A. alternata, regardless of application method or blueberry cultivar. PAA in general did not adversely affect general fruit quality or sensory quality of blueberries, though there was a slight enhancement of berry shrivel in a 85 µL L-1 PAA treatment of one of the cultivars. Use of PAA appears to be a promising means of reducing postharvest decay in blueberries.