apples, and presented weight loss, decay, and shriveling data. Kattan (44) 
developed a machine that packs fruit in perforated polyethylene consumer 
pouches, with 3 to 4 fruits per pouch and no tray. The pouches are connected 
in a continuous ribbon, but can be separated. 
Use of shrinkable films to immobilize fruit was an innovation of the 
early 1960's, Shrinkable polyethylene, polypropylene, polystyrene, polyvinyl 
chloride, polyester, plasticized vinyl, and Pliofilm became available (3, 28, 
30, 47, 70). Fountain (28) evaluated shrinkable films for overwrapping medium- 
size Delicious and Winesap apples at shipping point in Washington. “A consumer 
unit of 6 or 8 apples in a molded pulp tray was overwrapped with shrinkable 
film. Then packages were conveyed through a 300° F. heat tunnel. The film was 
drawn tightly around the package without damage to the fruit from the brief heat 
treatment. 
Shipping tests of this type of consumer package were made from Washing- 
ton to eastern markets in cell-type master containers, Fruit arrived with very 
little bruising, only 2.7 percent slight bruising on Red Delicious and 3.5 per- 
cent slight bruising on Winesap. Cost of material and labor for the shrink-film 
package was 2.2 to 2.4 cents a pound compared with 1.7 cents a pound for con- 
ventional tray-packed cartons. 
Fountain (28) developed a cell-type shipping container, in which each 
consumer package was held securely in an individual compartment by separators 
that prevented upper layers from pressing on lower layers, and substantially 
reducing bruising. 
Moyer (54) and Lins (46) described a shrink wrapping operation in the 
eastern United States in which a sleeve wrap (open ends) of 75-ST Vitafilm was 
used over molded pulp trays. Smaller apples were placed in trays holding 3 or 
4 pounds, Larger apples were packed by count in trays holding 4, 6, 8, or 10 
LEULe. 
Churchill (18) reported good expansion of shrink packaging for Golden 
Delicious (6 per tray) in Washington State in 1963, although total volume was 
still small. Shrink-wrapped trays of Golden Delicious packed in production 
areas in shipping containers arrived at markets in as good or better condition 
as Golden Delicious in cell-packed corrugated cartons. In another study with 
McIntosh apples (16), four types of packages were evaluated for protection of 
fruit during shipment. Cell cartons gave the most protection from rough han- 
dling, but apples prepackaged in trays with heat shrinkable film overwraps and 
packed in cartons were next best protected. 
Physiology of Packaging and Film Requirements 
Several investigators have studied the microclimate within various types 
of film packages containing apples or other fresh produce (19, 26, 37, 38, 39, 
48, 49, 65, 68, 74, 75, 81, 82, 86, 88). After packaging, apples continue to 
respire, use the available oxygen, and give off carbon dioxide, water, and heat. 
If the consumer package does not allow for entrance of oxygen, the supply is 
soon exhausted and respiration becomes anaerobic. In anaerobic respiration 
(respiration in absence of free oxygen), alcohol and carbon dioxide are pro- 
duced, which can produce an off flavor and eventually kill the tissue, Apples 
may also be injured merely by the accumulation of carbon dioxide. Hall (35) 
found that Granny Smith apples stored at 68° F. in 1.5-mil polyethylene bags 
accumulated 6 percent carbon dioxide in 6 hours and up to 12 percent carbon 
dioxide in 12 hours, 
40 
