10 BULLETIN 63, U. S. DEPARTMENT OF AGRICULTURE. 



during the -wmter and early spring months, when the prevailing outdoor temperature 

 is low, so low at times that the problem has been to protect the fruit from freezing rather 

 than to reduce its temperature by artificial means. During periods of extremely cold 

 weather refrigeration may be a distinct disadvantage rather than otherwise. With the 

 present refrigerator-car equipment, the insulation provided to keep the fruit cool 

 diu-ing transit must also be relied upon to protect the fruit from freezing. This it does 

 by retarding the cooling of the fruit and reducing its temperature very slowly, thus 

 enabling the car to reach the market before the contents are actually frozen. It is easy 

 to see that the length of time required to cool the fruit to an injurious extent depends 

 upon (1) the outdoor temperatvue, (2) the efficiency of the insulation of the car, and (3) 

 the temperatiu-e of the fruit at the time the car encounters extreme weather conditions 

 in the North. 



The present-day refrigerator car is only partially efficient during extreme weather. 

 There are many t^^es of refrigerator cars with varying insulation, but none are able 

 to withstand extreme cold for any considerable length of time without the use of 

 artificial heat, just as they are unable to keep the contents cool in hot weather with- 

 out the use of ice. It follows, then, that under ordinary conditions during cold 

 weather fruit which has been cooled by the use of ice during the early part of the 

 trip from Florida will be more liable to injmy from freezing than fruit which has not 

 been so cooled before it is subjected to extremely cold weather. The appreciation of 

 this point is of great importance in discussing the refrigeration of Florida oranges, 

 because a A^ery large proportion of the crop is moved during periods of excessively 

 cold weather in the North, although the temperature in Florida may be sufficiently 

 high to warrant the use of ice at the beginning of the trip. 



The investigations of the Bureau of Plant Industry have amply demonstrated that 

 Florida oranges may be transported to market under ventilation with a minimum 

 loss from decay, even during periods of warm and humid weather, if sufficient care is 

 used to preserve the skin of the fruit in a sound, unbroken condition. None of the 

 experimental shipments commented upon in this paper were refrigerated. The use 

 of refrigeration during transit to market must not be considered as a means to offset 

 the effects of rough or careless methods of handling. Icing can not permanently 

 prevent deterioration. The low temperatiue only temporarily arrests the develop- 

 ment of the decay fungi. As soon as the fruit has been unloaded in market it warms 

 up, and decay develops very rapidly if a considerable number of the oranges have 

 been injured by careless handling. As a result such fruit soon gains a reputation for 

 very poor market-holding qualities. It is as important to have the fruit reach the con- 

 sumer in good condition as it is to have it arrive in the market sound. 



A considerable number of shipments were iced during the season of 1912-13, 

 especially during January and during a later period of warm, humid weather, when 

 heavy decay developed in nearly all shipments. It is safe to say that the number of 

 cars handled under refrigeration during this season was greater than during all pre- 

 vious seasons together. Many of the shippers claim that they have been able to 

 place the fruit on the market in much better condition when shipped under refriger- 

 ation than when shipped under ventilation only. This conclusion is based upon a 

 comparison of iced and noniced shipments. It is probable, however, that the com- 

 parison was not always fair, for the reason that no systematic study was made of the 

 behavior of fruit of the same grade and quality under the two systems of shipment. 

 Nevertheless, the general opinion prevails among growers and shippers that icing has 

 resulted in material benefit to the fruit and has yielded increased returns. Refriger- 

 ation, therefore, bids fair to become an important factor in the handling and ship- 

 ment of the Florida citrus crop. 



During the past season, with its periods of excessively high decay, the Florida 

 Citrus Exchange strongly urged its members to move their fruit north under refriger- 

 ation. The recommendations of the exchange officials, in brief, provided (1) that the 



