The storage life o f harvested fruits and vegetables is influenced by their continued respiration and biochemical activity. Lowering the temperature, and modifying the atmosphere surrounding the product, can extend the shelf-life of the produce.Mushrooms (Agaricus bisporus) were placed into different structural containers covered with PVC films and stored at three temperatures. The effect o f key variables, such as temperature, respiration rate, critical and optimal concentrations of 0, and COz, package-weight/area ratio and film permeability, were studied.It was concluded that a highly perishable product, such as mushrooms, must be wrapped and refrigerated in order t o prevent transpiration and shrivelling. Modified atmosphere packaging (MAP) may be beneficial but was n o t found t o be essential. If a certain batch o f mushrooms respires faster than predicted, or is exposed t o large temperature fluctuations, MAP could have a damaging effect.Keywords: Modified atmosphere packaging (MAP); fresh mushrooms; shelf-life; film permeability. INTRO DU CTlO NThe storage life of harvested fruits and vegetables is influenced by their continued respiration and biochemical activity. Lowering the temperature, and modifying or controlling the atmosphere surrounding the product, reduces respiration and delays senescence, thus extending shelf-life. '9,In a sealed package, containing a fresh product, a modified atmosphere (MA) is created by respiratory oxygen uptake and carbon dioxide evolution. Consequently, equilibrium concentrations of oxygen and carbon dioxide are established, so that rates of gas transmission through the packaging material equal the produce respiration rate. The steady-state equilibrium will depend on several parameters, such as temperature, respiration rate, 0, and CO, permeabilities of the packaging material, fill-weight, free volume in the package, and film surface area.An optimum atmosphere should minimize respiration rate without danger of metabolic damage to the commodity. However, exposure of fruits and vegetables to 0 , levels below their tolerance limits and to CO, levels above their tolerance limits will cause anaerobic respiration and physiological disorders, respectively. 3,4For short-lived and expensive produce, of which mushrooms are a good example, there is an economic incentive to extend shelf-life by using modified