CONTROLLED-ATMOSPHERE STORAGE OF STARKING DELICIOUS 

 APPLES IN THE PACIFIC NORTHWEST 



By H. A. Schomer, Biological Sciences Branch, and 

 G. F. Sainsbury, Transportation and Facilities Branch 

 Marketing Research Division 

 Agricultural Marketing Service 



The atmosphere in controlled-atmosphere storage is characterized by lower oxygen 

 and higher carbon dioxide concentrations than normal air, which contains about 21 per- 

 cent oxygen and 0.03 percent carbon dioxide. Controlled-atmosphere (C.A.) storage has 

 been used commercially in England for many years and is being used increasingly in 

 New England and New York. The total C.A. storage capacity in the East is approximately 

 700, 000 boxes, according to Smock (10).^ 



In England and in the Eastern United States, such storage is used for varieties of 

 apples that cannot be stored long at 31° without developing flesh browning or other dis- 

 orders. In New York and New England, Mcintosh is the principal variety held in controlled 

 atmospheres. Mcintosh apples may develop serious brown core during long storage at 31°. 

 By the maintenance of a proper storage atmosphere and a temperature of 38°, brown core 

 is prevented and the storage life of the fruit lengthened. In addition, the market shelf life 

 of fruit after removal from controlled-atnnosphere storage may be several times as long 

 as that of fruit from regular storage. 



No C.A. storages for apples have been constructed in the Pacific Northwest, prob- 

 ably because the principal varieties grown there are tolerant of 31° F. storage and may 

 be held for long periods at that temperature. However, Smock (10) recently reported 

 benefits from controlled-atmosphere storage to a number of varieties, including Golden 

 Delicious and Delicious, grown in New York and Washington. Smock recommended 

 controUed-atmospheres containing about 3 percent oxygen and 2 to 3 percent carbon 

 dioxide, but Fisher (3) found that 2. 5 percent oxygen without any carbon dioxide was the 

 best atmosphere for storing Delicious apples, and that 5 percent carbon dioxide hastened 

 the onset of mealiness. 



The Delicious variety constitutes about 60 percent of the total Washington apple pro- 

 duction. Extensive new plantings, mostly red strains of Delicious, will further increase 

 the preponderance of this variety. Consequently, all possibilities for lengthening the 

 storage life and providing better quality fruit late in the season merit special attention. 

 Controlled-atmosphere storage offers such possibilities. 



The autumn movement of Delicious apples from the Pacific Northwest has been 

 educed in recent years by the increased production in the East of high quality fruit, 

 which enjoys a low-cost transportation advantage in that area. 



r 



During the 1953-54 storage season tests were run to determine the effect of C.A. 

 storage on the quality of Starking Delicious and Golden Delicious apples grown in the 

 area of Wenatchee, Wash. Experimental lots of these varieties were held at approxi- 

 mately 31° F. with three different controlled atmospheres. 



The objectives of this experiment were as follows: 



1. To determine the increase in storage life when Starking Delicious apples grown 

 in the Pacific Northwest were stored in C.A. storage. 



2. To compare the dessert quality of C.A. stored apples with that of fruit from nor- 

 mal air storage. 



1 Underscored figures in parentheses refer to Literature Cited, page 15. 



