208 DATEGROWING 



judicious picking at a certain stage of maturity, pas- 

 teurization, chemical treatment, and cleanliness in 

 handling. 



The principle underlying artificial ripening is, 

 subjecting the date to a process which kills the pro- 

 toplasm, or so changes it that the enzymes within the 

 cell protoplasm are liberated and mobilized so that 

 their characteristic action can rapidly proceed. 

 Many agencies can bring this about, and among them 

 are heat and moisture, gasoline, nitrous ether, and 

 various acids and alkalies. The essentials of a 

 ripening process are: 



1. Efficiency as to rapidity and completeness of 

 action. 



2. Preservation of flavor. 



3. No poisonous substance must be left in the 

 fruit. 



4. Convenience and economy in operation. 



5. As dates are hygroscopic they must not be 

 over exposed to moisture, as that favors souring. 



The most successful method at present, in Arizona, 

 seems to be a combination of exposure to carbon 

 dioxide gas with proper temperature and moisture, 

 a process resulting in fully ripened, well flavored, and 

 sterile fruit. Clean handling and proper shipping 

 containers complete the method. 



In California, at the Indio Experiment Station, 

 carbon dioxide is not found essential to the ripening 

 method employed. Climatic and seasonal differences 

 probably explain the varying results of different 

 methods employed. In Arizona the date grower has 

 to contend with rains at the ripening time, which the 

 California grower has not to face. 



