Ozone did reduce the spread to some degree, but a high percentage 

 of the peaches was nonetheless infected. Ozone, which is a fre- 

 quent agent in air-pollution injury to plants, did not injure the 

 peaches in these tests. 



Strawberri es : Pint boxes of strawberries had either a gray 

 mold-infected or a Rhizopus rot-infected berry placed in them and 

 then were placed at 35 F for 7 days with or without 0.5 ppm ozone. 

 Following storage, they were held 2 days at 60 F in air to test 

 shelf-life. Ozone had no effect in reducing decay of the berries, 

 and it caused the caps on the berries to shrivel and dry. 



Blueberries : Pint boxes of blueberries, not inoculated with 

 molds, were held for 2 days at 35 F with or without ozone and then 

 held in air at 70 F for 4 days. In another test, the fruit was 

 held 6 days at 60 F with or without ozone. In both tests, ozone 

 had no effect in reducing decay from field infections. 



Grapes : Two varieties of grapes were inoculated with gray 

 mold spores and held for 6 or 7 days at 60 F. The presence of 

 ozone during this time did reduce the growth of mold on the upper 

 surfaces of the bunches, but the berries were internally infected 

 and the undersides of the bunches were very moldy. 



Cantal oupes : Unipoculated cantaloupes were kept 7 days at 

 45 F pi us 5 days at 60 F with or without ozone. The gas reduced 

 the amount of surface mold on the fruit but did not reduce the per- 

 centage of fruit infected with molds. 



Green beans : Green beans were held 7 days at 45 F plus 5 days 

 at 60 F . The presence of ozone did not reduce molds on the beans, 

 and it caused blotchy brown areas to develop on 20% of the fruit 

 due to injury. 



It is apparent from these results that low concentrations of 

 ozone are of little, if any, practical benefit in reducing post- 

 harvest decay on these commodities. Higher concentrations of ozone 

 cannot be used because the ozone will injure the commodities in 

 numerous ways. Even 0.5 ppm caused injury to 2 of the commodities 

 in these tests. 



The full report ("Effects of ozone atmospheres on spoilage of 

 fruits and vegetables after harvest," USDA Marketing Research Re- 

 port No. 801) can be obtained free from the Office of Information, 

 U.S. Department of Agriculture, Washington, D.C. 20250. 



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