3370 



TRANSPORTATION 



plants are expensive to build and operate, and where 

 the harvesting-season is short, the benefits from pre- 

 cooling must be very marked to justify the expense. 

 The salt and ice plants were designed to meet this 

 objection and have proved very practicable where ice 

 can be obtained at a reasonable cost and where the daily 

 output does not exceed a few cars. The principal 

 objections to car-precooling plants are the delay 

 between loading and preceding and the more or less 

 unequal cooling of the different packages in the car. 

 The delay incidental to finishing the loading of a car, 

 and the switching to a precooling plant is sometimes 

 considerable and, in some instances, the total delay 

 may approximate, to some extent, the slow cooling 

 under regular refrigeration. In a number of instances, 

 where car-precooling plants are in operation, in order 

 to minimize delays, there is too much of a tendency to 

 cut down the actual period of precooling, which results 

 in partial precooling only. Some of the reasons why 

 precooling is not more universally utilized may be 

 found in the rather heavy initial investment necessary 

 to build a plant, and the delay in shipment necessitated 

 by holding over for precooling. Especially is this true 

 with deciduous fruits where, in many sections, the ship- 

 ping-season is short and where each shipper is desir- 

 ous of getting his fruit or produce to the market as 

 quickly as possible. 



Precooling has been utilized more in connection with 

 the handling and shipment of citrous fruits from Cali- 

 fornia than anywhere else. It has apparently been 

 found to be profitable in the citrous industry largely 

 because of the long orange shipping-season, and for 

 the reason that it is utilized also to reduce the cost 

 of transportation. Precooled fruit from the growers' 

 warehouse plants is shipped with initial icing only dur- 

 ing the winter and spring season, the combined cost 

 of precooling and one icing being somewhat less than 

 the regular refrigeration rate. In Florida, precooling 

 of citrous fruits is more in the experimental stage. 

 Owing, however, to the short haul in warm territory 

 in winter, precooled fruit is usually shipped successfully 

 without any icing whatever. Comprehensive experi- 

 mental precooling investigations on a commercial 

 basis have shown decidedly favorable results from the 

 thorough precooling of lettuce and celery from Florida. 

 The principal berry-growing sections in California 

 and Washington have utilized precooling for several 

 years with the result that they have been able not only 

 to transport berries, such as red raspberries and logan- 

 berries, in better and sounder condition, but to widen 

 their marketing territory greatly. 



In a number of cases in which precooling has been 

 tried on a commercial basis, the physical handling of 

 the fruit has been too careless to result in any marked 

 advantage from precooling. This serves to illustrate 

 very forcibly that precooling should not be depended 

 on to overcome difficulties arising from improper hand- 

 ling. Another factor of no little importance is the 

 inability of the average refrigerator equipment to 

 maintain sufficiently low temperatures, even under full 

 icing, especially in the upper tiers, in transportation. 

 The good effects of quick and prompt cooling have 

 been nullified to a considerable extent by the rapid 

 rise in temperature of fruits or produce while in trans- 

 portation. No matter what system is employed, the 

 full value cannot be obtained from precooling unless 

 the produce has been properly and carefully handled 

 in the first place. Used as a means to overcome the 

 effect of rough handling, precooling only retards decay 

 and deterioration and simply transfers the troubles 

 from the first receiver at the market to the retailer or 

 consumer. Precooling must be thorough and as uni- 

 form as possible. The refrigerator car used for the ship- 

 ment of precooled produce should be sufficiently insu- 

 lated to maintain reasonably low and uniform tempera- 

 tures in transit. 



Temperatures in transit. 



The necessity for the maintenance of low tem- 

 peratures in transit has already been emphasized. The 

 question is often asked: How low ought the tempera- 

 tures in a refrigerator car to be for best results? The 

 only answer to this question is: As low as possible 

 consistent with safety from freezing. The same 

 principle applies as in storage. The lower the tempera- 

 ture above actual freezing, the more effectively are 

 ripening and the development and growth of decay- 

 producing organisms checked. While most of them 

 continue to grow very slowly at temperatures of 40 F. 

 or below, few germinate at this temperature. If, how- 

 ever, germination has already taken place, the best that 

 can be expected of refrigeration is to check their 

 growth and development sufficiently to allow of sound 

 delivery. The necessity for prompt and quick cooling 

 is therefore very apparent. 



The cooling in an ordinary refrigerator car is usually 

 rather slow and very unequal. It requires from six days 

 -to a week thoroughly to cool a load of oranges in tran- 

 sit and several days to cool wrapped deciduous fruits. 

 Unwrapped fruits in open containers cool relatively 

 fast because of the opportunity for free air circulation 

 around each individual fruit. The lower tiers cool 

 relatively fast in any load, especially near the ice- 

 bunkers. There are marked differences in temperature 

 between the ends and middle of the car, and between 

 the top and bottom tiers. In the quick-ripening fruits 

 these temperatures are reflected in the condition of the 

 fruit in the various positions in the car. Very often 

 the upper tiers are 15 to 20 higher in temperature 

 than the bottom tiers and have ripened to such an 

 extent as to make it necessary or desirable to sell them 

 separately from the remainder of the fruit in the car. 



One of the principal problems in transportation and 

 refrigeration of fruits and vegetables in transit is to 

 secure quicker and more uniform cooling throughout 

 the car. This can be done, to some extent, through 

 methods of loading and stowing and care exercised at 

 time of loading to retain as much as possible of the 

 refrigeration within a pre-iced car. With deciduous 

 fruits and vegetables, cars intended for loading should 

 be pre-iced several hours before loading begins. 



The shipper in loading should not only stow the load 

 so as to prevent shifting and breakage in transit but, 

 first of all, so as to facilitate free circulation from both 

 ends to the middle of the car. If crates are used, this 

 can be done by leaving straight uninterrupted aisles 

 between rows from one end to the other. Cleats between 

 each layer from bottom to top will also facilitate quicker 

 cooling. Racks so constructed as to provide a space of 

 4 inches between rack and floor for free circulation of 

 cold air from each bunker toward the middle of the car 

 underneath the load will greatly facilitate quick cooling 

 of every package in the load. In loading fruit into pre- 

 iced cars, it is very commonly the practice to leave both 

 doors open during the entire period of loading. Much 

 of the refrigeration is lost in this way which could 

 easily be conserved if more care was exercised to open 

 the doors only when absolutely necessary. 



In so far as methods of loading and stowing are con- 

 cerned, the responsibility for the safety of the load and, 

 to some extent, its quick cooling rests on the shipper. 

 The other factors, however, in actual transportation 

 that have to do primarily with quick cooling and the 

 maintenance of low temperatures in transit and free- 

 dom from breakage are factors for which the carriers 

 must share responsibility. When properly prehandled 

 produce has been stowed and loaded correctly, both as 

 regards liability to shifting in ordinary freight handling 

 and as to facilitating air circulation and quick cool- 

 ing, a shipper has largely fulfilled his responsibility so 

 far as products in transportation is concerned. Fol- 

 lowing this, the responsibility for the safe transporta- 

 tion of properly loaded product rests almost entirely on 



