Transportation, handling, and microbial growth performance of molded fiber and expanded polystyrene apple trays

Abstract

Washington State apples are shipped all over the United States for retail sales. Adequate packaging is needed to minimize apple damage during distribution. Two common materials used for apple trays are expanded polystyrene (EPS) and molded fiber (MF). A recent industry change from MF to EPS trays provoked an interest in exploring the performance difference between the two. Distribution environment hazards include shock, vibration, and compression forces. Prior work has focused only on comparing vibration or shock performance of EPS and MF trays used in protecting apples. In this study, a variety of typical hazards encountered between case pack and retail preparation are considered on a larger sampling scale. The shock, vibration, and interlayer dynamic compressive forces are simulated as well as free‐fall drops possible with manual handling of the cases. A novel device and test method is developed to simulate the forces because of human hands removing trays of apples from the case at retail. Further, a microbial analysis of worst case apple condensation is performed to compare the tray materials effect on apple microbial populations. It is concluded through physical and microbial testing that there is no statistical difference in the physical protection or the growth of microbial populations between EPS and MF apple trays. Most significant tray damage is observed in the EPS trays because of free‐fall drop testing. Apple tray material selection can be shifted to other factors such as cost or consumer preference.