TRANSIT-REFRIGERATION Charges on Fruit Reduced by Recent Discoveries

Fruit- and vegetable-producing areas in the far western States are peculiarly dependent upon specialized efficient and economical means of transportation to get their crops to the consumer in an attractive and marketable condition.

California ships annually upwards of 70,000 carloads of oranges, 15,000 of lemons, 2,500 of asparagus, 29,000 of cantaloups and other melons, 6,000 of carrots, 6,000 of cauliflower, 8,000 of celery, 50,000 of grapes, 85,000 of lettuce, 10,000 of peaches, 10,000 of pears, and 3,000 carloads of tomatoes, besides substantial quantities of practically every other fruit and vegetable found on the markets of this country. Roughly, 50 percent of the commercial apples of the country, or about 40,000 carloads, are produced in the Pacific Northwest, chiefly in the Yakima and Wenatchee districts of Washington, while the same area likewise ships about 8,000 carloads of pears and substantial quantities of berries, cherries, onions, potatoes, and other fruits and vegetables.

The development of fruit and vegetable production in these areas, and the prosperity and welfare of all the people engaged therein as well as of the communities supported by these industries, are based entirely upon the successful transportation of the produce to market.  Furthermore, the constant and varied supply of fresh fruits and vegetables on the market has changed the dietary habits of the Nation.  No longer are fruits and vegetables to be had only seasonally. Most of them are available from some producing area every month in the year, always in fresh, attractive condition, and usually at prices within reach of the average consumer.

In the development of this vast industry and the tremendous business which it supports, refrigerated transportation has played a vital part. The successful application of transit refrigeration to the different products has been brought about in large measure through investigations of the Bureau of Plant Industry concerned with determining the proper stage of maturity at which to harvest and methods of handling, packing, precooling, storage, and transportation.

In earlier years when prices were relatively higher and returns were good, emphasis was naturally placed upon the use of methods that would reduce to the minimum every hazard of spoilage and every condition that would adversely affect the appearance of the product, and would thus deliver only the highest quality goods to the market. The successful shipment of oranges from California was effected primarily by showing the industry how to control blue-mold decay by the use of careful handling methods and satisfactory transit refrigeration. The latter involved improvements in refrigerator-car design and construction and facilities for keeping the cars fully iced throughout the transcontinental trip. Later, methods of precooling were developed to reduce the temperature of the fruit quickly and thus still further to remove the hazard of decay, since blue mold does not make much growth at temperatures below 45° F. It is much more important to reduce the temperature of the fruit quickly and have it cold at the start of the journey than to deliver it at a relatively low temperature at the market.

Modifying Transit-Refrigeration Methods

Based on results of these earlier studies, some of the most recent investigations of the Bureau have been directed to the possibility of modifying transit-refrigeration methods. It has been found that instead of reicing orange shipments once every 24 hours, as was formerly the practice, only one reicing in transit is necessary,if the fruit is cold at the start. With this fact demonstrated, and the development of many details of procedure to cool the fruit without excessive cost, a reduction in. the refrigeration rate was secured from the railroads which saves the industry $30 to $40 a car, or upwards of a million dollars annually. This saving may well mean the difference between profit and loss in fruit growing.

FIGURE 72.—A railroad-car precooling plant showing method of connecting cold-air ducts to ice-bunker openings. Cold air is blown in at one end of the car and is returned to the refrigerating coils from the other end.  The air is reversed periodically to provide uniform cooling. It requires about 8 hours to precool a carload of oranges, and at plants such as the one illustrated, at San Bernadino Calif., an entire trainload can be handled at one time.

In all the recent investigations of the Bureau on transportation methods the primary objective has been similarly to develop every possible economy, and to reduce costs, while still delivering the produce to market in satisfactory condition. The most recent modification of shipping methods for California oranges, put into effect in August 1934, affords a saving of $15 a car in the charge for precooling when no ice is used in transit. It was found that during the fall and spring when the weather in the eastern part of the country is cool the only refrigeration needed for oranges is enough to keep them from warming up excessively while crossing the hot desert region of the Southwest. By blowing cold air at a temperature of about 25° F. through the loaded cars (fig. 72) for about 8 hours the temperature of the loaded fruit can be reduced to 40° or lower. Then the cars are closed tightly until after the desert region is crossed and the fruit is satisfactorily protected during this hazardous part of the trip. Thereafter the ventilators are opened and advantage is taken of the cool outside air.

   The shipment of pears from the Pacific Northwest offered other opportunities for important modifications in refrigeration with substantial savings to the industry. Pears are far more exacting in their temperature requirements than are oranges, but it was found that when they are properly precooled the size of the carload could be increased from 520 boxes, which formerly was standard, to 640 or even 744, thus reducing the number of cars required to handle the crop and giving the railroads a greater revenue per car. Furthermore, since the cost of transit refrigeration is upon a carload basis, the heavier load resulted in a lower cost per box.  The savings to the northwestern fruit industry by use of new methods developed in experimental work of the Department are conservatively estimated at more than a million dollars annually. Practically every kind of fruit and vegetable moving to domestic or overseas markets has similarly benefited in some manner from the Department’s handling, transportation, and storage investigations.

D. F. FISHER and C. W. MANN, Bureau of Plant Industry.