Transport
Read about Transport in the Standard Cyclopedia of Horticulture
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Transportation of horticultural products. Commercially, fruits and vegetables are grown primarily for profit. Whether the business of fruit- or vegetable-growing results in profit or in actual loss to the grower depends on a great many factors. Among the more important are quality and quantity of production, distance from markets, cost of transportation, the condition in which the produce reaches the markets, methods of marketing, and the supply and demand. In present-day fruit-growing, especially when the localities of production are often thousands of miles distant from the larger markets, there is no factor of greater importance than rapid and efficient transportation. Every fruit-grower is, or should be, aware of the necessity of safe and rapid transportation, together with the delivery of perishable produce at the markets in sound attractive condition. Soundness and freedom from decay or deterioration are fundamental to profitable marketing, therefore to successful fruit-growing. All the labor and moneys invested in production are wasted if the products cannot be transported and delivered in good condition. Transportation is the link that connects the producer with his market, his zone of distribution being determined largely by the cost of transportation and absolutely by the distance over which the produce can be shipped in sound marketable condition. This distance will necessarily vary with the variety of fruit, the localities in which grown, cultural methods, care exercised in handling and preparing it for shipment, the promptness with which it is cooled, and the temperatures maintained in transit. The factors above mentioned are the more fundamental ones governing the condition of horticultural produce in transportation. It is clear, therefore, that successful transportation depends not only on conditions in transit but on the pre-handling of the produce prior to shipment. The responsibility for the condition of these products when delivered at the markets is a common one as between producers, shippers, and carriers. The very best refrigeration that is practicable cannot, be expected to deliver perishable products in sound merchandizing condition that have been badly handled prior to loading or shipment. Nor can such produce properly handled be delivered in good marketable condition without adequate refrigeration in transit during warm weather or sufficient protection against freezing in the cold weather. The railways of the United States annually pay out millions of dollars in claims on account of breakage, decay and deterioration, freezing, and other damage in transit of perishable produce. This does not begin to cover losses sustained by the shippers in claims that are not paid, or deterioration for which no claims are made, and the injurious effect on the price received for the produce actually sound. The economic losses to consumers, carriers, shippers, and producers, especially consumers and producers, who finally shoulder the greater part of the burden, are enormous. This great wastage of the nation's food-supply is an important factor in the high cost of living and is very generally one of the main reasons for losses instead of profits to the growers or producers. The most important fact in this connection is that most of these losses are unnecessary and preventable. As the decay and consequent losses occur in transit, it is of the greatest importance that growers, shippers, and carriers have a clear and accurate knowledge of the fundamental factors governing condition of fruits and vegetables in transportation. Few commodities are more subject to decay and deterioration in transit than are fruit and vegetable crops. In considering the transportation of these products and their behavior in transit, it is absolutely essential that the fact be kept in mind that fruit and vegetables are living organisms with a definite span of life beginning in the orchard or field and ending normally in actual death-decay. It must be remembered, therefore, that, in preparing these products for shipment, in transportation, and through all stages to the ultimate consumer, one is dealing with real organisms, the life-span of which will be lengthened or shortened by methods of handling and conditions in transportation. A correct interpretation of the reasons for the losses from decay and deterioration in transit depends on accurate knowledge of types of troubles that destroy the market value of fruits and vegetables. The prevention of these losses must be based on a clear understanding as regards the relation of the development of these troubles to methods of handling prior to shipment, and to temperature conditions in transit. The types of troubles that may destroy or lessen the value of these products are of two kinds, decay and skin-blemishes. In ordinary transportation the former is by far of the most importance, while in storage skin-blemishes may be very important factors. Decay may result either from attacks by fungous or bacterial organisms, or through physiological breakdown which may be termed natural death decay. The organisms causing decay in transportation may for convenience be divided into two groups, those which are parasitic, or which may cause decay of sound uninjured fruits, and those which are saprophytic or which have not the power to attack the sound unbroken skin of fruits or vegetables. Parasitic fungi causing decay in transit are usually orchard or field diseases that ordinarily can be controlled through proper cultural sanitation practices in the fields or orchards. Saprophytic organisms are responsible for by far the largest proportion of losses due to fungous decay in transportation and can be controlled only through careful and correct handling methods in the harvesting and preparation of the fruit for shipment. Physiological breakdown or death-decay hinges largely on proper handling methods and temperatures in transportation. It is plain, therefore, that the fundamental factors influencing, to the greatest extent, the behavior of fruits and vegetables in transportation come under the following heads: (1) Cultural; (2) maturity at time of picking; (3) care exercised in all handling operations; (4) promptness of cooling; precooling; (5) temperatures in transportation. Cultural history of the crop. In so far as cultural practices determine the crop's freedom from disease when harvested and its inherent keeping quality, are cultural operations responsible for condition of these crops in transportation. Of especial importance are the methods of orchard or field sanitation. Field or orchard diseases attacking growing fruits or vegetables very often cause serious decay in transit. Peaches from orchards or sections affected with brown-rot (Sclerotinia) or Monilia usually show serious development of brown-rot after shipment. In certain humid sections of the Pacific coast, for example, the prevalence of brown-rot makes long-distance shipment of cherries and fresh prunes an extremely hazardous venture. Certain vegetable crops, such as lettuce, celery, and tomatoes, when transported long distances, sometimes develop serious decay in transit through diseases that attack the growing crops in the fields. Decay in transportation, caused by diseases commonly affecting crops in field or orchards, can be controlled only through proper orchard- and field-sanitation practises. While the rapidity of the development of such decay in transportation can be controlled, to some extent, by quick prompt cooling and the maintenance of very low temperatures, the only real preventive lies in the control of these diseases in fields or orchards. Maturity at time of harvesting. The picking-maturity of peaches, muskmelons, and other quick-ripening fruits is governed largely by the distance from market and general experience as regards the carrying quality of such fruits at different stages of maturity under ordinary refrigeration. When they are to be shipped for considerable distances, the usual practice is to pick and pack them while still so green, hard, and immature as to be unfit for immediate consumption. Sometimes they are harvested in such a green state that they do not properly ripen in transit, and while not entirely worthless from a marketing standpoint, their poor eating quality necessarily results in very low prices. Fruits from certain sections have undeservedly gained a reputation for poor quality because the consumers never have had an opportunity to taste any properly matured fruit. There is no questioning the fact that if the quick-ripening fruits entering into long-distance transportation could be harvested at much nearer full maturity, that is, hard-ripe, and transported to the consumer in sound condition, both producer and consumer would benefit greatly, the former in increased returns, the latter in securing a more wholesome and palatable fruit. The reason for the present condition is largely found in the notion that such fruits must be picked while still very green and hard to carry in sound condition to the market. To some extent this idea is well founded. Greater care, however, in all handling operations, with prompt cooling, will enable growers and shippers successfully to handle the quick-ripening fruits at more advanced stages of maturity. When precooling facilities are available, it has been demonstrated that it is not only possible but practicable to harvest such fruits as peaches and pineapples at advanced stages of maturity as will give the consumer a product possessing its maximum fine quality and wholesomeness. When such facilities are not available, much can be accomplished toward the same end through proper and careful handling, prompt loading and the stowing of the load in the car in such a way as to facilitate circulation and consequent quick cooling or refrigeration. The practicability of successfully transporting more nearly tree- or plant-ripened fruits, possessing the maximum fine quality of the variety when delivered to the consumer, will depend both on the grower and the carrier. The grower must exercise, first of all, the greatest care in handling and get his fruit under refrigeration quickly. The carriers must provide refrigeration facilities in which the product can not only be cooled faster but transported at lower temperatures than is ordinarily obtained in the average equipment. What has been said above; relative to the desirability of harvesting certain fruits at much advanced stages of maturity, does not, of course, apply to such fruits as pears, lemons, and fruits or vegetables which should be picked green in order that they may possess their maximum fine quality when finally ripened or cured. Care in harvesting and handling. The care exercised in harvesting and preparing horticultural products for shipment determines, to the greatest degree, its shipping or keeping quality. Extensive investigations conducted on a commercial scale by the Bureau of Plant Industry, United States Department of Agriculture, for a number of years, covering a wide range of fruits and vegetables, have clearly and conclusively demonstrated that decay in transit and after arrival at the market is due very largely to rough methods of handling. The fungous organisms causing decay gain entrance through mechanical abrasions of the skin made in picking, hauling, packing, or other handling operations. Every injury or breakage of the cells of the skin offers lodgment for fungous spores which, given proper moisture and temperature conditions, germinate and produce decay. Both high temperatures and moist atmosphere favor rapid development and growth of these organisms. Temperatures are usually fairly high during the harvesting season, as is frequently the humidity. During periods of muggy or rainy weather, the conditions are ideal for the germination and development of fungous spores, and almost every injury is certain to result in decay. The fundamental consideration, therefore, in all handling operations is the preservation of the skin in a sound and unbroken condition. Nearly all growers and handlers of fruit or vegetables realize that rough handling, resulting in mechanical abrasions of the skin, is more or less responsible for decay occurring in transit. Few, however, have a clear idea of the extent of mechanical injuries made in ordinary commercial handling, nor do they realize fully the importance of the most careful work, or what constitutes proper and careful handling of a perishable product. In a short article it is obviously impossible to go into details as to how injuries are made in handling from field to car. The handling operations involved in the harvesting and preparation of the citrous fruit crop for shipment may serve as a very good example. In the harvesting of citrous fruits the mechanical abrasions may result from cuts made by the clippers used in severing the fruits from the tree, from contact with thorns on the trees, from dropping the fruits into the picking-sack or field-box, rough handling in loading, and jarring in hauling over rough roads or on springless wagons. Additional injury may result as the fruit goes through the washing-machines, brushes and driers, and over the sizers, and into the bins. Long sharp stems also cause much injury as the fruits roll against one another in the picking-sack, field-box, and the various operations of washing, drying, grading, and sizing. The pickers and packers, where gloves are not worn, may cause much injury through finger-nail cuts. The washing of fruit in dirty water, or slow and incomplete drying, both afford ideal or favorable conditions for infection of every injury and the consequent development of decay. The so-called soft fruits require even more careful handling to avoid bruising and to preserve the skin of the fruit in a sound unbroken condition through all the operations of picking, hauling, and packing. Peaches are very commonly injured through the pickers exerting too great pressure with the thumb or other fingers when removing the fruit from the tree, by rough handling in loading, and bruising in the various operations of grading and packing. While sizers or graders have been used to a considerable extent in the handling of peaches, most of the graders now in use afford too many opportunities for injury to be universally recommended in the handling of such crops. In red raspberries, for example, the most serious decay results from too great pressure on the berry when removing it from the core. The use of three fingers instead of two minimizes the pressure and danger of injury. The inclusion of over-ripe berries in cups or crates intended for long-distance shipment is also a very prolific source of decay. The marketing or distributing zone of such fruits and berries can be extended by several thousand miles by the exercise of a little more care in picking and grading. In grapes the most serious injuries result from the loosening of the berry from the pedicel, and it requires the most careful handling, both in picking and packing, to avoid this type of injury which is chiefly responsible for the frequent excessive decay occurring in transportation. Careful handling involves the exercise of thoughtfulness in the manipulation of the fruit from tree to car in order to preserve the skin of the fruit in an unbroken sound condition. It necessitates the most careful supervision of labor. It means simple and the minimum amount of machinery for washing, drying, sizing or grading, and constant attention to keep it clean and in perfect order. The whole handling problem is an economic one related to systems of both hiring and supervising labor. In citrous states cooperative associations have found it necessary to take over the field handling as well as the packing-house handling to insure uniformity of careful work. Where each grower does his own picking, the bad handling of one nullifies, to a large extent, the good work of the other, especially if the fruit from the different growers is pooled and shipped in the same cars. The success of this method of cooperative handling depends largely on having the right kind of manager and foreman, men who not only know what careful handling is and means, but who can secure such work from every man in the organization having anything to do with the physical handling of the fruit. The system of paying later is largely responsible for carelessness in handling and decay in transit. Too much emphasis cannot be laid on quality as the tendency is at present decidedly in the direction of attaching too much importance to quantity. Quantity at the expense of quality is poor economy in the handling of any perishable fruit crop. There is considerable question and argument as regards the best picking-receptacle, particularly as to whether picking-sacks or -bags are preferable to pails or baskets or other similar containers. For citrous fruits, and other hard thick-skinned deciduous fruits, canvas picking-bags are usually preferable. Peaches and other thin-skinned fruits, that are very liable to injury by the rubbing of one fruit against another, ought to be picked in receptacles with rigid sides. In such receptacles the fruits will not be subjected to more or less rubbing against one another as they would be in a picking-bag where every fruit necessarily moves somewhat with the movement of the picker. Quickness and promptness of cooling. Next to care exercised in the physical handling of the fruit, temperature is the most important factor in determining the life-span of the fruit. The question of temperature in the handling of fruits for transportation is related primarily to the promptness and rapidity with which the produce is cooled and the maintenance of low temperatures in transit. Most of the fruits and vegetables are harvested during periods of high temperatures. The physiological and chemical changes that constitute ripening proceed very rapidly at high temperatures and but very slowly at temperatures slightly above freezing. High temperatures shorten the life-span of the fruit, both through rapid ripening and the rapid development and growth of decay-producing organisms. The low temperatures retard the ripening processes as well as the germination and growth of fungi causing decay. It is therefore, of the greatest importance that the produce be cooled as promptly and quickly as possible after removal from the tree or field. Delay of a few hours of the more quick-ripening fruits after harvesting in the field or packing-house during the heat of the day may mean the shortening of the normal life-span of such fruits by days. Prompt cooling is essential, whether this is accomplished by precooling before shipment or slower cooling in a refrigerator car. Advantage also may be taken of cool night temperatures by allowing the fruit to remain unpacked out in the open over night and packed later in the cool of the morning. More cooling can usually be accomplished this way over night than in a whole day in a refrigerator car, especially if the fruit is wrapped and tightly packed. Precooling. The prompt quick cooling of produce prior to shipment has been termed "precooling." It is usually accomplished by mechanical means in warehouse plants before loading in cars, or in car-precooling plants after loading. In the latter case the precooling is accomplished by forcing large volumes of cold air through the load in the car. More recently smaller warehouse plants have been built and successfully operated using ice and salt for refrigeration. As to which system is the best is still more or less of an open question and depends largely on local conditions. Warehouse plants have the advantage in so far as the cooling of the produce can be commenced immediately after packing without any delay. The cooling is usually more uniform and very often the plants are used as warehouses to held fruits and vegetables in good condition for considerable periods when, on account of market conditions, or for any other reason, it is desirable to do so. Mechanically cooled warehouse-precooling plants are expensive to build and operate, and where the harvesting-season is short, the benefits from precooling 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 precooling 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 shipping-season is short and where each shipper is desirous 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 California 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 during 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 experimental 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 loganberries, 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 handling. 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 transportation. 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 uniform as possible. The refrigerator car used for the shipment of precooled produce should be sufficiently insulated to maintain reasonably low and uniform temperatures in transit. Temperatures in transit. The necessity for the maintenance of low temperatures in transit has already been emphasized. The question is often asked: How low ought the temperatures 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 temperature 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, however, 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 transit 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 concerned, 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 freedom 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 cooling, a shipper has largely fulfilled his responsibility so far as products in transportation is concerned. Following this, the responsibility for the safe transportation of properly loaded product rests almost entirely on the transportation company both as relates to freedom from breakage and efficient refrigeration. The care exercised in handling freight trains and cars in switching is mainly responsible for the condition of a properly stowed load as regards shifting, breakage, and the like. The efficiency of the refrigerator car is primarily responsible for the quickness of cooling and the maintenance of uniformly low temperatures in transit as well as liability to freezing damage in cold weather. The efficiency of a refrigerator car depends not only on the quantity, quality, and condition of insulation but on the size of the car, the kind of ice-bunkers, and facilities for effecting free circulation and quick refrigeration of all packages in the car. Salt, as a means of securing lower temperatures in refrigerator cars, is in use extensively in the transportation of meats and similar products requiring temperatures below freezing. It has been used only very sparingly with fruits. Recent tests with somewhat modified equipment indicate that salt can be used to good advantage in securing quick cooling and in maintaining the necessary low temperatures in transit. The methods of icing and charging for refrigeration in transit vary considerably in different sections of the country. From Pacific coast points to the East, the carriers, under certain blanket rates, assume all responsibility for refrigeration in transit from point of shipment to destination. In the deciduous fruit sections all cars, unless precooled, go out under standard refrigeration, that is, pre-icing before loading and full re-icing enroute at all regular re-icing stations to destination. The refrigeration rate is uniform on all cars to any one point. Under the standard refrigeration rate for citrous fruits, the cars are usually not iced until after loading unless otherwise requested by the shipper who pays a somewhat higher rate for pre-iced cars. With citrous fruits from California, various other rates are in effect permitting one pre-icing and a re-icing before final shipment, or precooling, and one icing with no re-icing in transit. When the growers do their own precooling and initial icing with no re-icing in transit, a charge is made only for the use of the car and freight on the ice hauled in the bunkers. In the shipment of fruits from Florida there is not only the standard refrigeration rate which calls for full re-icing at the designated icing stations enroute, but there is also another rate for half-icing, which means the refilling of the bunkers at the various icing stations to one-half of their capacity, the racks on the floors of the bunkers being raised so as to hold the ice in the upper half of the bunker. In the eastern states the so-called blanket refrigeration rate to various points is not used to any considerable extent in the shipment of fruits and vegetables. The refrigeration charge to the shipper is usually based on the amount of ice consumed in transit as shown by the carriers' records at icing stations. The shipper pays for the ice actually used and the icing is done according to the instructions furnished by him on the bill of lading. If the shipper orders full refrigeration in transit, the cars are re-iced at the regular icing stations. The shipper, however, has the option of giving other instructions if he so desires, namely, either the number of icings enroute or the icing stations at which he wishes the cars to be re-iced. Under the standard refrigeration rates, applying from the Pacific coast territory, the responsibility for refrigeration in transit rests entirely with the carriers. In eastern territory the responsibility is divided between the shipper and the carrier. Freezing in transit. The transportation of fruits and vegetables in sound condition in transportation is related not only to efficiency of refrigeration but protection against freezing. During protracted periods of cold weather, such as sometimes occur in the northern and eastern states in the winter, the protection of fruits and vegetables in transit is a real problem. While a number of factors enter into the question of freezing protection in transit, the principal one is insulation. Aside from condition and quantity of insulation, shippers and carriers have both attempted to minimize the danger from freezing by heavy tight loading and lining the inside with heavy paper, sometimes using several thicknesses, by putting in floor-racks and by placing stoves in the bunkers or in the middle of the car. Both tight and heavy loading are desirable when there is danger from freezing. The tight load tends to hold the heat more effectively and the heavier the load the more heat there is to draw on. Lining with heavy building-paper, or other paper of similar character, gives added protection. Certain roads have found floor-racks of decided value in minimizing the damage from freezing. Results both experimentally and commercially fully justify their use to minimize frost damage as well as an aid to more effective refrigeration. The use of stoves or heaters is hardly to be commended, as frequently the injuries from overheating certain parts of the car result in deterioration as regards quality, condition, and appearance that exceed what the freezing damage would have been. In the transportation of potatoes during the colder months from northern states such as Maine, heater cars are used to a considerable extent. Ordinary freight cars with specially constructed bins so as to provide an air-space between floor and sides of car and the load are used very largely also. A stove is placed in the middle of the car and a messenger accompanies three, four, or more cars to keep the fires going properly. The heat from heaters either outside or inside the cars is depended on more than the insulation to maintain temperatures above freezing. CH
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References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
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