Films must be used for consumer packaging that will allow entrance of 
sufficient oxygen and escape of carbon dioxide to prevent damage to fruit. In 
1946, Platenius (65) showed that a single 1/4-inch vent hole in a film-wrapped 
consumer package would prevent anaerobic respiration. Many types of films do 
not have adequate permeability to the respiratory gases to prevent possible 
harm, so use of perforated or ventilated films has become standard practice. 
Scott and Tewfik (75), Claypool (19), Schomer (74), Hardenburg (37, 38), Hall 
(35), Duvekot and van Hiele (26), Avall (6), Marcellin (48, 49) and Tomkins 
(81, 82) have elaborated on the need for adequate film permeability or artifi- 
cial film ventilation. 
Tomkins (82) has shown that the concentration of carbon dioxide rises 
until the pressure is such that the rate of escape by diffusion through the 
film or through perforations is equal to the rate of production. The concen- 
tration of oxygen meanwhile falls until either the rate of passage of oxygen 
into the bag is equal to the rate at which it is used up or anaerobic conditions 
are established. 
Scott and Tewfik (75) tested 15 kinds of film for packaging Gallia Beauty 
apples. After 5 days at 72° F., the oxygen within the packages ranged from 0.3 
to 5.6 percent and carbon dioxide from 14 to 30 percent. These high carbon 
dioxide and low oxygen levels had deleterious effects on the apples. The extent 
of alteration of the atmosphere in the packages depended upon the temperature 
and the time, as well as the type of film. The respiration rate of apples 
packed in several of the films was lower than for unpackaged apples. Harden- 
burg, Schomer, and Lieberman (39) showed that adding a small amount of ventila- 
tion to packaged apples had a negligible effect on weight loss. Apples bagged 
in LSAT cellophane and stored 7 days at 70° lost 0.6 percent moisture in non- 
vented bags, 0.8 percent in bags with two 1/4-inch holes, and 0.9 percent in 
bags with many U-shaped die-cut flaps. Two 1/4-inch holes in these cellophane 
bags kept the oxygen at 19 to 20 percent and the carbon dioxide under 1 percent 
at 70°. No off-flavor developed during 2 weeks at 70° in sealed LSAT cello- 
phane bags. However, Jonathan, Winesap, and Golden Delicious packaged in sealed 
polyethylene or 120 FF Pliofilm bags developed fermentation flavors within 2 
weeks at 70°. These films should be ventilated if used for apples. Ritter and 
Thomas (68) found that the flavor of Rome Beauty apples stored 2 weeks at 35° 
in nonperforated polyethylene bags was inferior to that of fruit in perforated 
bags. 
Several reports show that a high relative humidity builds up within 
moisture-retentive packages from the water vapor given off by produce (19, 26, 
37, 74, 82). This high humidity, approaching 100 percent, favors the growth of 
decay-producing microorganisms. As a result, decay may be worse in consumer- 
packaged produce than in bulk. Hardenburg (37) showed that by increasing the 
number of ventilation holes in a film package, beyond those needed to let oxygen 
enter and carbon dioxide escape, the relative humidity could be maintained at 
more desirable levels of 90 to 95 percent. He suggested 16 %-inch holes for 
5-pound polyethylene bags of apples. In commercial practice, 16, 24, or 32 
perforations are commonly used for 3-, 4-, or 5-pound bags. Even with 16 to 32 
perforations, moisture loss from apples in consumer packages is markedly less 
than from nonpackaged apples. 
Schomer (74) studied numerous films for produce and concluded that choice 
of film depends on several factors, besides its value in preventing moisture 
loss and shriveling. Other factors were ease of handling, durability, appear- 
ance, transparency, cost, and adaptability to machine wrapping. 
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