The effect of a post-harvest heat-treatment on the storage behaviour of Cox's Orange Pippin apple fruits

Samples from a wide range of commercially grown Cox's Orange Pippin apple fruits were immersed in water at 45° C. for 10 min. to control rotting due to Gloeosporium spp. In two seasons the incidence of rotting following storage for 19 weeks at 3·3° C. (38° F.) was reduced to about 40% of the level in the untreated samples. However, there was a marked increase in the incidence of breakdown and core flush in the treated fruit, particularly when stored in a controlled atmosphere of 5% CO₂, 3 % O₂. A similar but less severe increase in the incidence of breakdown was also recorded in the second season in treated fruit stored in 2% O₂ (with continuous removal of CO₂). The treated fruit tended to develop a more yellow ground colour and softened more rapidly during storage in 5% CO₂, 3% O₂. It is concluded that the treatment advances fruit senescence and that the increased incidence of physiological disorders is likely to limit the use of this method for the control of Gloeosporium rotting in English-grown Cox apples.