Golden Delicious in tray-packed telescope-type corrugated cartons stored at 
32° F. Carbon dioxide within these folded-top liners ranged from 4 to 6 per- 
cent. 
Such nonsealed or folded-top liners may not allow adequate gas exchange 
for fruit in cartons some years, For example, one season Mattus (47) found 
severe injury in tray-packed Golden Delicious packed with folded-top polyethyl- 
ene liners when carbon dioxide reached 8 to 10 percent. An inverted tray was 
placed above the overlapped liner. Then, when telescope covers were added the 
liners were essentially sealed and the fruit suffocated. For safety, most 
liners for Golden Delicious are no longer sealed in the United States, 
In Australia, nonsealed liners are recommended to prevent shriveling of 
Yates apples because carbon dioxide has caused injury some years in sealed 
liners (51). This injury to Yates apples in sealed liners occurred in light- 
crop years. 
Stoll and Nyfeler (72) have stated that polyethylene readily takes up 
aromatic volatiles and that this can cause trouble in storage, 
Eaves (12) suggested that chemical inserts can aid in controlling the 
atmosphere in sealed liners. He used impermeable Mylar polyester film as a box 
liner and enclosed small polyethylene packets of hydrated lime to absorb carbon 
dioxide and packets of calcium chloride to absorb moisture, The desired level 
of carbon dioxide was maintained by adding 1/4=-inch holes or pinholes in the 
lime inserts. Oxygen was supplied by perforations in the Mylar liner. Use of 
lime inserts would appear to offer good possibilities for avoiding carbon diox- 
ide injury. 
Later, both Hardenburg (26) and Hansen (21) showed that a pound of hy- 
drated lime enclosed in kraft paper or waxed paper pads could be used in 1.5- 
mil polyethylene lined boxes of apples or pears to absorb carbon dioxide. This 
was a way of avoiding brown core and other types of carbon dioxide injury. A 
l-pound kraft paper pad of lime kept carbon dioxide below 1 percent in a bushel 
of apples packed in sealed polyethylene for 5 to 6 months at 32° F. (26). 
Without lime inserts, carbon dioxide ranged from 5 to 8 percent in sealed liners 
in six tests. Hansen (21), using waxed kraft paper to contain the lime, main- 
tained carbon dioxide at a desirable 1.6 to 2.8 percent in sealed poly-lined 
boxes of pears, 
Marcellin (42, 44, 45) and Leblond (38, 39) in France have done consider- 
able research on films other than polyethylene for apples and pears. Where six 
or more boxes are enclosed in film, ethylcellulose had a desirable permeability 
for Golden Delicious, They showed that fruit could be stored at relatively 
high temperatures of 12° C. (54° F.), if enclosed in ethylcellulose. Tomkins 
(75) showed how carbon dioxide and oxygen change in sealed packages of various 
films and discussed the attainment of equilibrium. He calculated the effect 
of package size and weight of apples on the equilibrium concentration of oxygen 
and carbon dioxide within packages of various films. Pratella and Battistini 
(60) studied the ratio of weight and surface of polyethylene film necessary to 
develop beneficial modified atmospheres, 
Tolle (74) developed a formula based on product need which should be 
useful in calculating approximate film permeability requirements for specific 
storage conditions. This formula considers five factors concerning the con- 
tainer and its contents and expresses the permeability requirements in terms of 
milliliters of carbon dioxide or oxygen per square meter of film per 24 hours 
at standard pressure and selected storage temperature. The equations, which are 
being tested in actual storage trials, appear to be a step toward obtaining film 
to meet specific packaging needs. 
55 
