12 CIRCULAR 740, U. S. DEPARTMENT OF AGRICULTURE 



cular bundles and extending as threadlike fibers throughout the flesh ; 

 and the appearance of sunken spots where the apples were bruised 

 while frozen. After apples have been badly frozen, the skin becomes 

 shriveled, the surface is discolored in irregularly shaped areas, and the 

 tissue beneath may be translucent and water-soaked or have some 

 shade of brown. Badly frozen tissue becomes dry and corky after pro- 

 longed storage. 



When slight freezing occurs near refrigeration coils or cold-air 

 ducts, the frost can be removed by raising the temperature at those 

 points to 32° F., but when the apples are frozen deep in the piles, 

 a storage-room temperature of 40° or above and an active circulation 

 of air between the packages will be necessary to thaw them out. The 

 fruit should not be moved while frozen, as this will result in severe 

 injury. The thawing of frozen apples at a temperature of 70° does 

 not result in greater injury than thawing at 32° to 40°, but a high 

 temperature is not recommended, because of its accelerated ripen- 

 ing influence. To prevent shriveling, the relative humidity should be 

 kept as high as possible during the thawing process, preferably above 

 80 percent. 



JONATHAN SPOT 



Jonathan spot is a skin disease giving the apple a freckled appear- 

 ance from small black or brown spots that appear usually on the 

 deep -colored areas. Although it sometimes develops on other varie- 

 ties, especially Rome Beauty, from a commercial standpoint it is of 

 importance only on the Jonathan. It may be confused with the black 

 spots around the lenticels caused by arsenic burn or with the brown 

 freckled appearance of Jonathans caused by other spray or washing 

 injuries, but these are distinguished by their appearing earlier in 

 storage, regardless of temperatures. The disease is prevented almost 

 entirely by picking before overmature and storing promptly at 30° 

 to 32° F. Jonathan spot is an indication of "old age," and its appear- 

 ance is a warning that the fruit is being kept beyond its commercial 

 storage period. It may develop on fruit still on the tree. 



WATER CORE 



Water core occurs in the fruit before it is removed from the tree. 

 As it is usually associated with advanced picking maturity, crops 

 severely affected are ordinarily not considered well suited for pro- 

 longed storage. The water-soaked areas gradually become smaller 

 during storage and, if they are not severe, may completely disappear. 

 Apples affected with water core never completely recover, however, 

 because the affected tissue has been weakened and is disposed to 

 internal break-down. In the Delicious, Rome Beauty, Stayman, and 

 other softer varieties, internal break-down may follow slight water 

 core at the fibrovascular bundles. Apples that have apparently made 

 a complete recovery while in cold storage frequently become worth- 

 less from internal break-down within 5 or 6 days after removal to 

 living-room conditions. 



The disappearance of water core is not hastened by storing the 

 apples in atmospheres of low relative humidity but rather by holding 

 them at temperatures that produce rapid ripening. As such ripen- 



