Hie Canadian Horticulturist 



Vol. XXXIV 



SEPTEMBER, 191 1 



No. 9 



The Pre-Cooling of Fruit 



J. A Ruddick, Ottawa, Out., Dominion Fruit and Cold Storage Commissioner 



THE beneficial results of pre-cool- 

 ing fruit, especially for long-dis- 

 tance shipment, are now so gener- 

 ally admitted and understood that very 

 little needs to he said on that point. For 

 early quick-ripening 

 apples and tender 

 fruits, the import- 

 ance of having the 

 temperature quickly 

 reduced after the 

 fruit is picked and 

 packed, cannot be 

 over - estimated. If 

 warm fruit is loaded 

 into an ordinary re- 

 frigerator car, it is 

 several days beiore 

 the temperature is brought down to the 

 minimum, no matter how much ice is 

 used. For that reason, the fruit must 

 be picked in a green condition and be- 

 fore it has reached its full quality, to 

 allow for the ripening in transit. 



Even though the fruit may arrive at 

 its destination in a sound condition, the 

 quality will not be as good as it would 

 have been if it had been allowed to have 

 become more mature before picking. 

 No matter how green certain fruits may 

 be harvested, the distance which they 



J. A. Ruddick 



ran he shipped in iced cars without pre- 

 cooling is very limited, if they are to 

 arrive in perfect condition. Pre-cooling 

 increases the distance for safe shipment, 

 and thus extends the market enormously. 



The term "pre-cooling" has been 

 somewhat erroneously applied almost ex- 

 clusively to the method worked out in 

 California for the cooling of loaded cars 

 of fruit and vegetables. Strictly speak- 

 ing, pre-cooling includes any method of 

 cooling or chilling before shipment, and 

 while there are two or three large car 

 cooling plants in California, there are 

 some half-dozen smaller plants where the 

 pre-cooling is carried out in the packing 

 house. There is no difference in prin- 

 ciple, or in the results obtained, other 

 factors being equal, between car-cooling 

 and cooling in a warehouse, but cooling 

 in cars has some decided advantages 

 over the other method, where the condi- 

 tions permit of its being adopted, or the 

 volume of the shipments warrant the 

 necessary expenditure. 



The pre-cooling of fruit in cars is car- 

 ried out in the following manner. As 

 soon as the cars are loaded, or at least 

 as soon as possible after loading, they 

 are brought to the refrigerating plant 

 and connected to the system with flex- 



ible ducts which provide for the passing 

 of a current of cold air through the car. 

 The duct which carries the inlet, or cold 

 blast, is attached to a false door which 

 exactly fits the open door of the car, as 

 is shown in the illustration on page 200. 

 The outlets, or suction ducts, are fitted 

 in the same manner into one of the 

 hatches of the ice bunker at each end of 

 the car. Fans are used on both the 

 inlet and the returns to promote a rapid 

 circulation of the cold air. Canvas 

 baffles are hung temporarily in the car 

 to deflect the air current so as to force 

 it between the packages of fruit instead 

 of passing merely over the surface. 



The number of cars which may be 

 cooled simultaneously is limited only by 

 the capacity of the refrigerating plant 

 and the number of connections. The re- 

 frigeration required per car is equal to 

 about twelve tons of refrigeration for 

 twenty-four hours ; that is to say, if five 

 cars are to be cooled at once, and within 

 a reasonable limit of time, it would re- 

 quire a refrigerator plant of a capacity 

 of sixty tons of refrigeration in twentv- 

 fcur hours. 



With sufficient refrigerating power, 

 ears should be well cooled in four or five 

 hours, including the time required for 



A Large Pre-cooling Plant in California Where Twenty-four^Car* Can Be Cooled at the Sam* Time 



f 



