Impact of Storage Temperature Fluctuation on Modified-atmosphere Packaging of Fresh Produce

Abstract

Use of modified atmosphere (MA) as an adjunct to low temperature can be effective method for prolonging the shelflife of fresh fruits and vegetables. However, if storage temperature fluctuates, anoxic conditions can result and, consequently, the fresh produce quality can deteriorate rapidly. The objective of this investigation was to evaluate the effects of temperature fluctuation on the atmosphere inside the package and on the quality of packaged produce. Mushrooms (A. bisporus, U3 Sylvan 381) were packaged in rigid containers (4 liters) fitted with diffusion windows to obtain an atmosphere of 5% O2 and 10% CO2 at 4C. Temperature fluctuation had a major impact to the atmosphere inside package. During the first fluctuation sequence, O2 level depleted to 1.5% and CO2 increased to 18%. When the temperature returned to 4C during the next sequence, CO2 level fell back to 10%, but O2 level remained at 1.5%. The quality of mushrooms stored under temperature-fluctuating conditions was severely affected, as indicted by the extent of browning, loss of texture, and level of ethanol in the tissue compared to mushrooms stored at constant temperature. It was clear from this experiment that under temperature fluctuation, even it occurs once, can seriously compromise the benefits of MA packaging and safety of the packaged product. It is thus necessary that MA packaging compensate for the additional permeability required that is caused by storage temperature fluctuations.