The 2012 ASHS Annual Conference

Modified atmosphere packaging (MAP) is a nearly universal complement to refrigeration in fresh-cut produce. Design of MAP for fresh-cut produce requires the knowledge of gas exchange rates by the product and via the semipermeable barrier enclosing it and the temperature effects on these variables. Models relating product and package variables are available to describe and predict changes in gas composition occurring in the MAP system, at equilibrium or under dynamic conditions. Despite our understanding of MAP engineering, fresh-cut operators often neglect the optimization of gas compositions inside the packages, likely because the benefits fail to materialize in the supply chain—even if relevant under experimental condition. The perception of quality in fresh-cut produce is based on attributes that have a physiological basis. These have different kinetics and are differentially affected by the partial pressures of oxygen or carbon dioxide. Physiological restrictions to the reduction of respiration rate by MAP need to be better documented in horticultural produce. In fresh-cut produce with low Km for respiration rate as a function of oxygen partial pressure, oxygen levels in MAP are not likely to significantly reduce respiration or to prolong shelf life. Under these conditions, there is little or no benefit in optimizing oxygen levels inside the package and the role of MAP is restricted to the protection from water loss and contamination. Evidence for the strong and differential effects of oxygen levels on individual flavor-important volatiles must also be featured in new recommendations for gas composition and MAP development. A better understanding of the physiological bases of the quality of fresh-cut fruit, including the physiological limitations to quality maintenance, will be very useful to foster innovation in the fresh-cut industry. Trial-and-error approaches can be replaced by science-based approaches based on physiological models.