Symptoms develop early in storage and may increase in severity with extended storage time. Evidence to date indicates that internal browning occurs as a result of CO 2 injury to the apple. Injury incidence and severity increase with increasing concentrations of CO 2 in the storage atmosphere. Later harvested fruit generally have greater susceptibility to internal browning and it has been shown in many fruit that diffusivity of CO 2 decreases as fruit mature and ripen. A reduction in the ability of CO 2 to diffuse out of the apple fruit would result in higher internal CO 2 concentrations and thus more chance of injury.
Internal browning can be more severe in fruit when watercore is also present.
The accumulation of sorbitol in the intercellular spaces would result in reduced gas diffusion in the affected tissue. Avoid harvesting overmature fruit. Harvest at the optimum maturity, especially for controlled atmosphere storage. Assure good air circulation in storage rooms to prevent pockets with higher CO 2 concentrations. Proper temperature management and good ventilation will prevent buildup of CO 2 .