SUMMARY 



Radiation- pasteurizing of strawberries would reduce spoilage loss by at least 

 enough to pay the cost of treatment, according to preliminary estimates of costs,, 

 Additional savings might be realized because (1) the shelf life would be increased, 

 (2) less in-store culling would be necessary, and (3) use of carbon dioxide gas as 

 a mold inhibitor could be reduced or eliminated,. For California strawberries shipped 

 to New York City, the present cost of the carbon dioxide treatment is about 0,3 cent 

 per pound. 



Considerable potential exists for reduction of spoilage loss of fresh peaches, 

 tomatoes, oranges, and grapefruit, but more technical research information is 

 required before estimates of economic feasibility of radiation-pasteurization can be 

 made. The U,S, retail value of recent spoilage losses of these commodities is 0,2 

 cent to 4,9 cents per pound of shipping weight. Tomatoes are at the top of this 

 range. 



Technical research at the University of California, Davis, reveals that if fresh 

 strawberries are radiation- pasteurized by an optimum dose of 200 kilorads it is 

 possible to hold spoilage losses during marketing to about 5 percent, depending on 

 amount of infection with spoilage organisms at harvest. Accordingly, estimates of 

 spoilage loss savings, on the basis of the recent U,So retail price of 45,2 cents per 

 pound, would range from 4,3 to 4,5 cents per pound shipped to market, depending 

 on the extent to which the practice was adopted by the strawberry industry. Savings 

 in this range are substantially more than enough to pay for estimated radiation- 

 pasteurizing costs. 



Estimated radiation-pasteurizing costs for an applied dosage of 220 kilorads by 

 selected facility type, size, and hours of annual operation are: 



Facility 

 type 



Facility 

 size 



Total 

 investment 



Cost per pound 



2,000 hrs. 

 (half year) 



4,000 hrs. 

 (full year) 



Cobalt 60 



Cobalt 60 



3-Mev. X-ray machine. 



1 kw. or 68,000 curies $167,287 

 3 kw. or 204,000 curies 316,862 

 3 kw. 522,000 



2.9 cents 

 1.7 



2.4 



2.0 cents 

 1.1 

 1.6 " 



These cost estimates are based on a 2- shift operation, 5 days per week. Cobalt 

 60 and X-ray machine facilities are assumed to have 30 and 35 percent net utilization 

 efficiencies, respectively, and source use factors of 95 and 80 percent, respectively. 



In this analysis, the radiation-pasteurizing cost estimates for cobalt 60 facilities 

 declined when the facility size was increased from 1 kilowatt to 3 kilowatts or when 

 the hours of annual operation were increased from 2,000 to 4,000 for either facility 

 size. For the 3-kilowatt X-ray machine, this increase in the length of operating 

 season decreased the cost per pound by one-third. Accordingly, facility size and 

 the expected hours of annual operation should be considered as major economic 

 factors when investing in food irradiators. It should be emphasized that radiation 

 capacity can be enlarged by replicating small irradiators as well as by installing 

 larger ones. 



The adoption of radiation-pasteurization by the strawberry industry would 

 represent a significant increase in the barriers to entry of new shipping firms be- 

 cause of the investment requirements. Consequently, one would expect shippers to 



- v - 



