36 CIRCULAR 659, IT. S. DEPARTMENT OF AGRICULTURE 



Because apples are not highly perishable, like peaches or strawberries 

 for example, and move during the cool seasons, many shippers order 

 their cars shipped under ventilation. Under this service no particular 

 control of the temperature of the load is possible; the vents are kept 

 open at all times when the outside temperature is above a stated mini- 

 mum, usually 32° F., and are closed when the outside temperature drops 

 to this minimum. If the fruit is warm when it is loaded, cooling in 

 transit depends entirely on lower outside temperatures. If the fruit is 

 colder than the outside air, the load will warm up. This is particularly 

 likely with shipments from cold storage. Such shipments should never 

 be forwarded under ventilation service. If transit refrigeration is not 

 desired, they should be billed "Plugs in. Vents closed to destination." 

 Thus the refrigeration stored up in the cold load can be utilized through- 

 out the trip. 



Movement under this service or under ventilation provides the 

 cheapest services available to the shipper. From the standpoint of the 

 condition of the fruit, the use of ventilation is justified only with apples 

 that are intended for immediate use. With apples intended for storage 

 at destination, ventilation service jeopardizes the potential storage life 

 of the fruit because of the rapidity with which the ripening process pro- 

 ceeds at higher temperatures (p. 9). Consequently, as a rule, apples 

 that move under ventilation are not worth as much as those that are 

 refrigerated in transit. This does not mean that ventilated shipments 

 necessarily sell for less than refrigerated consignments, but it does mean 

 that they are likely to give less satisfaction to the consumer, thereby 

 doubtless indirectly affecting the market for apples in general. Shippers 

 who use ventilation service indiscriminately are to that extent increas- 

 ing the hazards of the industry and inviting dissatisfaction among con- 

 sumers, which must affect the demand for apples. 



Shipments can be billed to move under standard refrigeration or 

 various modifications of it. Under standard refrigeration the bunkers 

 of the car are initially iced to capacity and are refilled at all regular icing 

 stations en route (usually at least once every 24 hours), and the car is 

 delivered with bunkers at least three-fourths full. When shipments are 

 precooled or are loaded out of cold storage and move under standard 

 refrigeration, maximum protection is obtained. 



Sometimes modified refrigeration services can be utilized to effect 

 savings in cost without sacrificing efficiency of refrigeration, and shippers 

 are utilizing such services to an increasing extent. It is possible, how- 

 ever, that some apple shippers are going too far in this direction. The 

 apple does not ripen as rapidly as some other fruits, but every day that 

 it is kept above the optimum storage temperature means a progressive 

 shortening of the time before it will become fully ripe and presently over- 

 ripe and undesirable or unsalable. Consequently, protective services, 

 providing relatively high temperatures during the transit period, inter- 

 ject an element of hidden damage to the potential storage quality of 

 the fruit. The degree to which this damage may be hidden, or the time 

 at which it will become apparent in the ripening of the fruit, depends on 

 the condition of the apples at time of shipment and then temperature 

 while in transit. It is more likely to be serious with varieties like Jona- 

 than, Rome Beauty, and Delicious, which are often left on the trees 

 until past proper picking stage in order to get more red color, than with 

 later keeping varieties, such as Winesap and Yellow Newtown. 



