Fishman, S., Department of Statistics and Operations Research, Agricultural Research Organization, Volcani Center, Bet Dagan 50 250, Israel
Rodov, V., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50 250, Israel
Ben-Yehoshua, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50 250, Israel

A model was developed to study gas dynamics in a package containing fresh fruit. The model calculates the gas balance taking into account the processes of fruit respiration and transpiration, as well as the permeation of gases and water vapor through a perforated packaging film. Equations are suggested to describe the permeation of gases and water vapor through perforations in the film. The model enabled the time course of O2 consumption, CO 2 evolution and the humidity changes in the modified atmosphere enclosed in the perforated film to be computed analytically when the respiration rate depends linearly on O2 concentration, as is the case, for instance, for mango fruit. The weight loss of the fruit in this modified atmosphere was calculated by means of the model. The model enables the investigators to evaluate the film specifications and the package parameters which will provide the best conditions for storage of a given commodity.