ANNUAL REPORT, 1941 91 



respiration unless ventilation was provided. One tight can was left undisturbed 

 with a subsequent CO2 accumulation of over 60 percent of the total atmosphere. 



Through controlled ventilation, one can was operated approximately on the 

 English system of 10 percent oxygen and 11 percent carbon dioxide. With an 

 open 3/8-inch vent near the base of the can, respiration at 40° reduced the oxygen 

 below the 10 percent level. By controlling the amount of leakage through a 

 similar hole at the top of the can, the desired atmosphere Was maintained fairly 

 well. Only a very small top opening was needed to allow sufficient air leakage to 

 counterbalance oxygen utilization. 



On March 1, one can was opened. The atmosphere in this can had been 

 maintained at less than 1 percent of oxygen with the CO2 averaging around 12 

 percent. The apples were in poor condition with scald, skin ruptures, and some 

 internal breakdown. The more highly colored apples were in the best condition 

 both in appearance and eating quality. The flesh was rather soft. A slight 

 alcoholic taste was evidence of anaerobic respiration. 



On May 1, another can was opened. The ox^'gen content of this can had 

 averaged about 2 percent with the CO2 ranging between 3 and 10 percent. Most 

 of the apples were in good condition with excellent color and no evidence of scald 

 or internal breakdown. There was some soft rot and mold where apples had 

 been injured. Quality was fairly good. A duplicate can was opened two weeks 

 later and here, also, the apples were in good condition though the quality was 

 mediocre. A rather high acidity was a contributing factor. 



The can which was operated on the English s\'stem was examined on May 13. 

 The oxygen level had varied between 8 and 15 percent. With this system, the 

 sum of the oxygen and CO2 always equals about 21 percent. There was no scald, 

 core breakdown, or rot, but quality was rather poor. 



Where flushing with nitrogen was utilized and a very limited amount of ventila- 

 tion provided, apples were still in good eating condition on May 13. The oxygen 

 in the can had varied between approximately 2 and 5 percent and the CO2 between 

 2 and 12 percent. Just why this treatment gave the best results is not clear 

 unless it was due to the frequent change of atmosphere in the can. The apples 

 (at 40° F.) were better than checks kept at 32°-33° F. 



These tests indicate that more uniform control of the atmosphere in a modi- 

 fied-atmosphere storage room is a requisite to the successful operation of such a 

 room. Undoubtedly, the wide fluctuation in the composition of the atmospheres 

 in the cans was a determining factor in lowering eating quality. 



The storage room which was "gas-proofed" in 1940 was not sufificiently tight to 

 allow respiration to reduce the oxygen to the desired 2 percent level. A contrib- 

 uting cause of this failure was the fact that brine coils and the shape of the room 

 allowed for only partial filling. This room was opened for inspection at 10 a. m. 

 on February 24 and closed again at 5 p. m., resulting in a total loss of the arti- 

 ficial atmosphere. The oxygen was again lowered to around 10 percent which 

 proved to be the minimum obtainable. The room was opened on March 24 and 

 the fruit placed in another room at 32° F. The Wealthy and Gravenstein apples 

 were past good eating condition; Cortland were fair to good; Delicious were very 

 firm and in excellent condition. Golden Delicious were also in excellent condition 

 and, where individually wrapped, these fruits showed no shriveling. Mcintosh 

 comprised the bulk of the apples. These were fairly ripe but not too much so for 

 immediate use. Quality was good and somewhat better than that of similar 

 apples stored as checks at 32° F. (Checks stored at 40° F. in normal air showed 

 internal breakdown.) There were considerable differences between different 

 lots of fruit. In general, the late picked Mcintosh had the best quality. High 

 color was associated with high quality. Some rot was in evidence on individual 

 fruits. Many apples did not hold up well at room temperatures, largely because 



