Effect of chlorine atmospheres on the development of rhizopus rot [Rhizopus stolonifer] and gray mold [Botrytis cinerea] on stored strawberry fruits

Gray mold and rhizopus rot, caused by Botrytis cinerea and Rhizopus stolonifer, respectively, are major diseases of strawberry (Fragaria xananassa) fruits, causing significant economic losses during storage. In this study, the effect of chlorine atmospheres on spore viability and mycelial growth of B. cinerea and R. stolon fer and on the development of gray mold and rhizopus rot on stored strawberries was evaluated. The results showed that spore mortality in R. stolonifer and B. cinerea was complete following a 6 h exposure to a chlorine atmosphere of 10 mg per litre of moist air, while mycelial growth of R. stolonifer and B. cinerea was completely inhibited at concentrations of 5 and 20 mg/L, respectively. At concentrations as low as 10 mg/L, chlorine provided a marked reduction in incidence of rhizopus rot and gray mold on strawberries after a 9 h exposure period. For both diseases, a chlorine atmosphere of 20 mg/L reduced the incidence by a minimum of 60% without affecting strawberry color or firmness. The results of this study suggest that exposure of strawberries to chlorine atmospheres represents a potential method for controlling postharvest gray mold and rhizopus rot.