Controlled atmosphere package

Claim 1

A container for retarding the maturation of respiring fresh produce selected from the group consisting of fruit, vegetables, or flowers contained therein by creating within the container a preselected carbon dioxide and oxygen concentration in the presence of said respiring fresh fruit, vegetables or flowers, said containers being constructed of a substantially gas-impermeable material completely enclosing said fresh fruit, vegetables or flowers, said gas impermeable material having a gas-permeable panel in one or more its walls to provide a controlled flow or flux of CO 2 and O 2 through its walls, where the panel is a microporous plastic membrane that is a biaxially oriented film comprised of a blend of a propylene homopolymer and a propylene-ethylene copolymer having an ethylene-moeity concentration of 2% to 5% by weight, filled with 40% to 60% of calcium carbonate, based on the total weight of the film, and having an oxygen permeance between about 77,500 and 465,000,000 cc/m 2 -day-atmosphere, the permeance and area of the membrane being such as to provide a flux of O 2 approximately equal to the predicted O 2 respiration rate for not more than 3.0 kg of the enclosed fruit, vegetable or flower, and the carbon dioxide permeance of the membrane being such as to maintain the desired optimum ranges of carbon dioxide and oxygen sufficient for optimum retardation of the maturation process of said produce for not more than the said 3.0 kg of enclosed produce.