COLD STORAGE FOR APPLES AND PEARS 9 



to growing conditions and may become noticeable on the tree or after 

 the fruit has been harvested and stored. Leaving apples on the 

 tree until they are mature often reduces loss from bitter pit or pre- 

 vents its subsequent development in storage. Crops of susceptible 

 apples intended for storage should be held at 30° to 32° F. for 2 

 months before being packed so that affected fruits may be sorted 

 out. 



INTERNAL BROWNING, OR BROWN CORE 



The terms "internal browning'' and "brown core" are used, respec- 

 tively, to designate the effects of low-temperature injury in Yellow 

 Newtown and Mcintosh apples. The Yellow Newtown grown in 

 the Pajaro Valley in California is especially susceptible, and in this 

 variety the injury commonly appears as elongated areas of brown 

 discoloration radiating from the core. As it progresses it may spread 

 throughout the tissue and resemble internal break-down. In Mcin- 

 tosh, as well as in Yellow Newtown and some other varieties, it 

 is characterized at first by a slight brown discoloration between the 

 seed cavities that may later progress until the entire core area becomes 

 brown, making the fruit unmarketable. Susceptible apples should not 

 be stored at 30° to 32° F. but at 36° to 40° to prevent or minimize 

 losses during storage. In districts where internal browning and brown 

 core are serious storage hazards, the application of controlled-atmos- 

 phere storage should be considered {22). 



INTERNAL BREAK-DOWN 



Internal break-down, recognized by a more or less general brownish 

 discoloration of the flesh, usually outside the core area and at the 

 blossom end of the apple, is essentially death from old age. It 

 manifests itself variously in different varieties. In Jonathan an 

 area on one side or in a zone beneath the skin may become brown 

 and dry while the rest of the flesh is crisp and juicy. This is some- 

 times spoken of as "Jonathan break-down." It is associated with 

 fruit harvested at an advanced stage of maturity and may occur early 

 in the storage season. 



In other varieties internal break-down may appear as brownish 

 streaks in ripe, mealy tissue, later becoming badly discolored, dry, 

 and spongy. This is designated as "mealy break-down" and in some 

 varieties the skin often ruptures. Late in the storage season or after 

 removal from storage this disorder frequently occurs beneath bad 

 bruises, or in tissue near the core in a region affected with severe 

 water core at the time of harvest. The risk of loss from internal 

 break-down is negligible when apples are harvested at the proper 

 stage of maturity and stored promptly at 30° to 32° F. for normal 

 periods for the variety. When found in a storage lot, it should be 

 regarded as a signal for prompt disposal of the fruit. 



A somewhat similar type of discoloration occurs in the fruit of some 

 varieties in some districts before harvest. It is caused b} T a defi- 

 ciency of boron. This type of break-down does not become worse 

 while the fruit is in storage. 



669297° — 46 2 



