2 - 



But unfortunately, even such light doses prove to be quite injur- 

 ious to most fruits. Although the fruits are not killed by such doses, 

 they are changed. Most fruits are softened by the treatment, and some- 

 times, as with grapes and pears, very greatly softened. Color is some- 

 times affected: peaches are made redder, while plums are sometimes 

 prevented from turning blue, and pearls develop a mottled green-and- 

 yellow instead of a yellow color. But most serious of all, irradiated 

 fruits often fail to develop their normal flavor during subsequent rip- 

 ening. Since fresh fruits are prized for their characteristic flavors, 

 a. loss of these flavors is a prohibitive effect of a treatment. 



Another form of injury to fruits is a reduction of their normal 

 resistance to disease-causing fungi. Since light doses of radiation do 

 only injure, not kill the fungi, this is a very serious problem. If ir- 

 radiated fruits are stored for an extended period after treatment, they 

 very often develop more decay than non- irradiated fruits, for in time, 

 the fungi recover from the treatment while the fruits do not. Also, 

 if the fruits become re-contaminated with fungi, their resistance to 

 these organisms is less than that of unirradiated fruits. This means 

 that radiation could not be used prior to a long storage period; its use 

 would be restricted to a short time before the fruits would be used, 

 such as for a reduction of decay during immediate marketing. 



Another problem is expense. An irradiation facility is a very ex- 

 pensive piece of equipment, and one that requires great skill and elab- 

 orate precautions for operation. Although it has been found that sprout- 

 ing of potatoes can be prevented by a very light dose of radiation and 

 without other injury to the tubers, only in certain situations would ir- 

 radiation of potatoes be economical, at least at the present stage of 

 technology. Such a situation now seems to exist in Canada. 



So, it can be seen that there are many problems confronting fruit 

 irradiation. But conspicuously missing from this list of problems is 

 the one that immediately comes to mind in a discussion of irradiation. 

 Irradiation does not make the fruits radioactive. The gamma rays are 

 the product of a radioactive source. They are not themselves radioac- 

 tive, nor do they make the objects they strike radioactive. Irradiated 

 foods are not radioactive '. 



Numerous experiments have been made on many different kinds of 

 fruits under many types of conditions. In these experiments, only one 

 fruit has consistently responded well to irradiation, and that is the 

 strawberry. The market life of strawberries is usually extended 2-3 

 days by irradiation, without injury to the fruit. For a fruit as per- 

 ishable as strawberries, this extension of market life is quite signif- 

 icant. Research is continuing on this crop, and it is quite possible 

 that in the near future irradiated berries will be arriving on our mar- 

 kets from California. California offers a. unique potential for this 

 operation, for its largest production area has a harvest period of at 

 least 3-4 months, with a fairly uniform volume of production during this 

 period. This produces an economic situation that cannot be matched in 

 the East. 



