acquaint growers with what is known about watercore and what might be 

 done to reduce losses resulting from it. This publication is available 

 from your County Extension Service or from William J. Lord, French Hall, 

 University of Massachusetts, Amherst 01002. 



A************** 



COOLING APPLES IN BULK BOXES 



WilliajTi J. Lord 

 Department of Plant and Soil Sciences 



Rapid cooling of fruit in storage is an extremely important phase 

 of cold storage management. Cooling of apples from field temperature 

 to 32°F within 2 or 3 days instead of 4 to 6 weeks can make a great deal 

 of difference in the keepability of apples. With the adoption of bulk 

 boxes by the apple industry, the cooling of fruit in these large con- 

 tainers becomes a problem of extreme importance if optimum storage life 

 is to be obtained. 



Research by G . 0. Patchen and G. F. Sainsbury (TJSDA Marketing Re- 

 search Report No. 532, 1962) has shown that a bulk box constructed with 

 either the sides or bottom having approximately 8 to 11 percent free 

 area (air space between boards) will provide cooling characteristics as 

 good as those of standard field crates on pallets. Free air space on 

 the sides gave cooling results comparable with free air space on the 

 bottom of the bulk boxes. 



Previous studies by Sainsbury showed that when containers of fruit 

 are placed directly in contact with outside walls, heat is transmitted 

 through conduction that affects the temperature of the fruit. The fruit 

 temperature may be 1° or 2°F higher or lower, than fruit in adjoining 

 bulk boxes, depending on whether outside temperatures are higher or 

 lower than those inside. To prevent this from occurring, the bulk boxes 

 should be stacked at least 6 inches from outside walls. Similar space 

 is needed near the inside ^^/alls to insure adequate air circulation past 

 and through the stacked boxes. 



The rows of stacked boxes should be parallel to the flow of air from 

 the diffuser or duct openings. With two-way-entry pallets, a row of 

 boxes constitutes an almost solid barrier to the flow of air, and placing 

 the stacks perpendicular to the flow of air impedes air movement. More 

 uniform holding temperatures are obtained when stack rows are parallel 

 to air flow. 



Stack rows should be made up of bulk boxes of similar size, so that 

 the fork space of the pallets is continuous from front to back of the 

 row, allowing a continuous air channel. Although the bulk boxes may be 

 nearly similar in height, any difference is cumulative. A 1-inch dif- 

 ference in height in each layer can blank off the channels at the top 

 of the stack. 



