are to be cooled by convection on a pallet, the vents in containers should be 
arranged to line up and provide a continuous passage from one exposed face of 
the load to the other (72). Hall (36) showed stacking patterns recommended for 
quick cooling of cartons on pallets and described open-chimney, parallel, and 
cross-stacking arrangements. 
Sainsbury (71) found that apples in unvented cartons often took three 
times as long to cool as in wooden boxes and the fruit remained two degrees 
warmer at equilibrium. He tested different amounts of carton ventilation and 
recommended two vents (3/4'"' x 2") at each end. Vented cartons with perforated 
trays allowed tray-packed apples to cool in half the time required for unvented 
cartons and provided performance equal to that of the old standard wrapped pack 
in wood boxes. The vents and perforated trays allowed an equilibrium tempera- 
ture only 0.8 degree above storage air temperature, Sainsbury (71) stated that 
stacking for good cooling should allow a surface exposure equal to two ends of 
a carton. 
Fisher (27) also found that tray- and cell-packed cartons were signifi- 
cantly slower in cooling when unvented. Only with two side vents and two end 
vents was carton cooling as fast as in wood boxes. Top boxes in stacks cooled 
more rapidly than center boxes, as might be expected. Spacing between rows and 
stacks was most important, Fisher stated that cooling with rows 3% inches apart 
and stacks 3/4 inch apart was better than with rows 1% inches apart and stacks 
tightly together, With the smaller spacing between rows, it took 4 days longer 
for f£ouLit to reach-35- EF. 
Guillou (34) showed that venting corrugated cartons speeded cooling by 
exposing some of the surface inside the box. He used a rule of thumb that each 
1 percent of box surface removed, reduces fruit cooling time by about 5 percent, 
Guillou reported that wood boxes and corrugated cartons cool at about the same 
rate when stacks are equally exposed in storage. 
Olsen, Patchen, and Schomer (60) showed that cartons tightly stacked 
together cool slowly and never reach a temperature as low as in bulge-packed 
wood boxes. They noted that vents in cartons did not take the place of proper 
spacing. Their results showed that perforated trays and the small vents being 
used commercially in cartons did not markedly increase the cooling rate of 
enclosed fruit. But proper spacing greatly facilitated cooling of cartons com- 
pared with close stacking. Hall (36) reported similar test results in 1962. 
Truscott (83, 84) has developed much information on ventilation of wooden 
containers to facilitate cooling. He reported that both top and bottom of 40- 
pound containers should have a minimum of 20 square inches of ventilation open- 
ings to allow adequate cooling. 
Noordzij (56) presented the theoretical approach to cooling fruit in con- 
tainers by calculating cooling curves. 
Shadburne (76) tested various truck loading patterns with McIntosh apples 
in corrugated cartons in shipments from New York to Florida. Load patterns 
which contained air channels the entire length of the load permitted better 
refrigeration and more uniform fruit temperatures in transit. 
Consumer Packaging 
Consumer packaging or prepackaging of fresh produce developed along with 
the growth of the supermarket. Prepackaging of apples and other produce was 
necessary if produce departments were to become self-service, as in other de- 
partments. Pioneering research on produce prepackaging was directed by Hauck 
38 
