Nov 13 1919 Nature and Control of Apple-Scald 213 



In the laboratory tests a small but powerful ozone machine was used. 

 In the preliminary experiments the ozonated air was used in its full 

 strength as it came from the machine; but it injured the apples, soon 

 producing brown dead spots at the lenticels. In the final experiments 

 the air from the ozone machine was reduced to half strength by mixing 

 with an equal volume of normal air. The apples used in the tests were 

 Grimes from Vienna, Va. They were picked August 2 1 and the experi- 

 ments started the following day. The fruit was stored in 8-liter jars 

 that were fitted with 2 -hole stoppers. Once every week ozonated air 

 was drawn through these jars, the incoming current being freed at the 

 bottom of the jars and the outgoing current taken from the top. The 

 process was continued for 5 minutes and the jar then tightly corked and 

 allowed to stand closed for the next 24 hours, after which the ^^-inch 

 stopper was removed and the jar left as a moist chamber for the remain- 

 der of the week. At the end of the ozone treatment the air from the 

 exit tubes had a strong smell of ozone, but after 24 hours no ozone odor 

 could be detected in the air of the j ars. Part of the apples were stored at 1 5 ° 

 and part at 0° C. In each experiment, control jars of apples were main- 

 tained that were identical with the others in every respect, except that 

 in the weekly treatment normal air was drawn through instead of the 

 ozonated air. Notes were taken at various times on the amount of 

 scald and on the quality of the fruit, but no contrast of any kind was 

 found between the apples that were treated with ozone and those that 

 were not. 



In the commercial cold-storage experiments, the ozone was obtained 

 from a large 12-cylinder machine of the type most commonly used in 

 egg storage rooms. The machine was operated from six to eight hours 

 a day and from five to seven days a week. Six barrels of Grimes apples 

 and six barrels of York Imperial were stored within a few feet of the 

 machine, while similar lots were held as controls in another storage room. 

 In each test, half of the apples were in ventilated barrels and half in 

 barrels of the usual commercial type. The final notes on the Grimes 

 apples were taken December 20 and the final notes on the York Imperial 

 on January 18. Both varieties had scalded badly; but there was no 

 contrast, in either the ventilated or unventilated barrels, between the 

 fruit that had been exposed to ozonated air and that which had not. 

 The results give little promise of scald prevention by increased oxi- 

 dation. 



Carbon dioxid. — Carbon dioxid is the gas produced in greatest 

 quantity by storage fruit and is therefore the one that might most nat- 

 urally be expected to produce harmful results. Experiments reported 

 in an earlier paper {2), however, have shown that apples stored contin- 

 uously in atmospheres having percentages of carbon dioxid similar to 

 those in commercial storage, or even considerably exceeding them, 



