Use and efficiency of disinfectants within a hydrocooler system for postharvest disease control in sweet cherry

Abstract

Commercial disinfectants were used within a hydrocooler to prevent postharvest diseases of sweet cherries and to extend the storage and shelflife durations. Different concentrations of sodium hypochlorite, peracetic acid, hydrogen peroxide and Citrox (R) were used in in vitro experiments whereby the toxicity of disinfectants on B. cinerea and P. expansum spore germination and germ tube elongation was investigated. Citrox (R) was the only disinfectant containing organic acids and flavonoids. The in vitro experiments demonstrated that disinfectants were effective in inhibiting spore germination and germ tube elongation. In in vivo experiments, fruits were inoculated with a suspension containing 1 x 10(6) cfu/mL B. cinerea and P. expansum spores and hydrocooled with appropriate disinfectant concentrations. Total microbial, fungal, and bacterial populations on fruit surfaces and in the water used for processing were reduced by all disinfectant applications. Fruits were packed in modified atmosphere packages and stored at 1 degrees C for 30 days and for 4 additional days on a shelf at 20 degrees C. During cold storage, fruits were evaluated in terms of phytotoxicity, and it was observed that Citrox (R), hydrogen peroxide, and ozonated water applications cause phytotoxicity in the both the stem and fruit. In contrast, no phytotoxic reaction was observed in sodium hypochlorite and peracetic acid applications. Fruit decay did not occur during cold storage but was seen during the shelflife period. Fruit decay was significantly reduced by sodium hypochlorite and peracetic acid applications. Sodium hypochlorite and peracetic acid applications within a hydrocooler were found to be efficient in preventing postharvest diseases of sweet cherries.