4. When temperature was kept either above or 

 below what was recommended for a cultivar, 

 greater amounts of disorders occurred. If the 

 incorrect temperature was combined with low 

 O2, the effect was made worse. 



5. Disorders that were intensified by very low 

 O2 and by low temperature were made worse 

 when CO2 was too high. The worst situation 

 was when very low O2 was combined with 

 both too low a temperature and too high a 

 CO2 level. All 3 factors interacted to worsen 

 problems. 



6. Ethylene scrubbing reduced disorders, 

 especially scald. However, either 6% CO2 or 

 extremely low O2 levels were just as effective 

 as ethylene scrubbing in controlling scald. 



7. When CO2 was higher than O2 in a storage 

 atmosphere, disorders tended to be increased. 

 Low O2 and high CO2 interacted to intensify 

 disorders other than scald, but the presence 

 of ethylene did not make these problems 

 worse. 



The technology involved in these studies 

 generally is not applicable in the Northeast fruit 

 industry today. However, the principles that are 

 seen in the results are meaningful. 



Clearly, anyone wishing to modify standard 

 storage recommendations must do so with great 

 care. Lowering O2, increasing CO2, or lowering 

 temperature possibly can reduce fruit softening, 

 but any of these factors can also lead to 

 disorders: low O2 injury, high CO2 injury, or 

 brown core. Thus, each modification involves a 

 calculated risk. What is generally not recognized 

 but is made dear in these studies is that if one 

 factor is changed (e.g., O2 is lowered), the risk 

 of damage from the change is greatly increased if 

 temperature is also changed or CO2 is also raised, 

 or worst of all, if all 3 modifications occur. 

 Most often, these additional changes are not 

 intended but result from operator errors or 

 equipment malfunctioning. The less reliable and 

 accurate that storage operation is, the greater is 

 the risk of a detrimental result if a storage 

 condition is deliberately modified. 



The corollary of this situation is: if a 



storage operator wants to modify standard 

 recommendations, storage management must first 

 be made precise and accurate. It is hazardous 

 to modify storage conditions without fu-st making 

 certain that storage operations are precise. If 

 you want to modify one condition, you must be 

 able to control other factors so that a stressful 

 combination of factors can be avoided. 



Should a storage operator discover that 

 adverse conditions have developed, he should 

 react by lessening the stress on the fruit. For 

 example, he may be operating at a less-than- 

 recommended O2 level when he discovers that 

 CO2 is creeping out of control. Since he is 

 losing control of CO2, he needs to increase the 

 O2 to avoid a double stress. The sooner this is 

 done, the less likely it is that damage will 

 result. 



Little and Peggie concluded that percent 

 CO2 should not exceed percent O2 in a storage 

 atmosphere. We recommend 5% CO2 and 3% O2 

 for Mcintosh, which appears to violate their 

 conclusion. However, ours is a very conservative 

 recommendation for Mcintosh, recognizing the 

 lack of sophistication in operation of most of 

 our storages, and is outside the consideration of 

 these authors. Yet, it is probably a good rule- 

 of-thumb that should you lower O2 below the 

 standard recommendation, you should follow 

 Little and Peggie's advice: keep CO2 lower than 

 O2. 



The results of this study emphasize that 

 storage operation is a system , in which O2, CO2, 

 and temperature are in balance. Preharvest 

 conditions, fruit maturity, speed of atmosphere 

 generation, and possibly ethylene enter into this 

 balance. Our standard storage recommendations 

 are deliberately conservative to allow for some 

 variability among these factors. If a storage 

 operator chooses to modify these 

 recommendations, he must be able to control the 

 other factors in this balance, so that multiple 

 stresses do not result. Unless he can provide 

 this control, he should not deviate from the 

 standard recommendations unless he is prepared 

 to accept possibly serious development of 

 disorders in fruit during and after storage. 



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