OZONE IN RELATION TO STORAGE OF APPLES 



19 



in color was classified as green and constituted the majority of the total. 

 The apples were packed in boxes without wraps or shredded paper.. 

 In a preliminary examination on March 3, 1943, while the apples were 

 still in storage at 31° F., no scald was found. On April 21 the apples 

 were placed at 70° for 1 week in order to allow any potential scald 

 injury to become manifest. Final inspection on April 28 revealed that 

 ozone had reduced the prevalence and severity of scald. 



When the apples were exposed to 3.25 p. p. m. of ozone for the entire 

 storage season 20.5 percent of the red fruit and 9.1 percent of the green 

 became scalded (table 9). In contrast, 76.7 percent of the red fruit 

 and 85.6 percent of the green in the nonozonized lots became scalded. 

 These results were surprising because ordinarily the green skin is more 

 susceptible to scald than the red skin. Severity of the scald was like- 

 wise greater in the nonozonized lots, a higher percentage of the fruit 

 being classed as severely scalded than as either slightly or medium, but 

 in the ozonized lots the greater percentages of scalded fruit appeared 

 in the slight and medium classifications. In spite of the reduction of 

 scald in the presence of ozone, however, satisfactory control was not 

 obtained. 



Table 9. — Effect of 3.25 p. p. m. of ozone on the development of scald 



on Arkansas apples 



[Stored at 31° F. until April 21, when placed at 70° for 7 days; examined April 28] 



Ozone treatment and 



Total 



Fruit with scald 



description of fruit 



Slight 



Medium 



Severe 



Total 



3.25 p. p. m.: 

 Red fruit 



Number 

 146 



287 



185 

 243 



Percent 

 9. 6 

 2. 1 



22. ,2 



16. 5 



Percent 

 4. 1 

 4. 2 



25. 9 

 28.0 



Percent 

 6.8 

 2. 8 



28. 6 

 41. 1 



Percent 

 20. 5 



Green fruit 



9. 1 



p. p. m. : 

 Red fruit 



76. 7 



Green fruit 



85. 6 







None of the other varieties used in these investigations showed any 

 scald development, probably because they were fully mature at time 

 of harvest. 



These results are in agreement with those of Smock and Watson 

 (2 If) , who found a significant reduction in scald on Rhode Island 

 Greening apples. They stated that ozone did not control scald but re- 

 duced its intensity. Earlier investigators (i, #) reported that ozone 

 has no effect upon scald development. 



EFFECT OF OZONE ON QUALITY OF FRUIT 

 Ozone Injury 



No injury resulting from ozone was observed on any of the fruit 

 during the 1941-42 storage season when the ozone concentration aver- 

 aged 1.95 p. p. m. for the season. However, with the higher concen- 

 tration of 3.25 p. p. m. of ozone employed during the 1942-43 season, 

 considerable injury occurred and some was noticed on all varieties. 



