Environmentally Friendly Microperforated Containers for Improving Postharvest Berry Shelf Life

Strawberries and blueberries consumption have increased considerably in the last years due to consumer’s convenience and health benefits awareness. Berries are mostly sold in vented clamshell containers made of poly(ethylene terephthalate), PET, or poly(styrene), PS. However, a rapid weight loss of berries during storage due to the vents causes shriveling and wilting and hence reduces marketability. Authors’ previous research compared these containers with non-vented poly(lactic acid), PLA, and concluded that non-vented PLA containers could be an adequate choice for extending blueberries shelf life and reducing the plastic waste being landfilled. PLA was chosen because of its compostability and recyclability. Although, there was higher microbiological growth due to the high humidity inside the containers, sensory panelists significantly preferred blueberries in non-vented PLA containers to those in clamshells. The high CO₂ levels that are able to reduce fungal growth, cannot be achieved with non-vented PLA containers, but may be with microperforated lidding material. Its effectiveness on prolonging fresh product shelf life has been widely reported but so far only petroleum-based materials have been used. In this study, PLA was used as a bio-based alternative to petroleum-based, hence introducing the first microperforated PLA film. In this study, strawberries or blueberries were packed in rigid PLA containers and sealed with continuous or microperforated PLA films (0, 3, and 15 microperforations). PET clamshell containers were used as controls. Packages were stored at 23¢ªC and 55% RH. Physico-chemical properties (CO₂ and O₂ evolution, weight loss, fungal development, pH, and soluble solid content (SSC)) were analyzed at predetermined times. Strawberries and blueberries in clamshell containers showed significant weight loss (14.6% at day 4 and 22.0% at day 9, respectively) in comparison with that of PLA containers. Higher numbers of microperforations resulted in lower CO₂ development in the headspace, lower weight loss, and more fungal growth. Berries in microperforated PLA exhibited stable SSC while for those berries in clamshell containers, a slight increase was shown. Also, the flavor evolution of berries was determined. In conclusion, microperforated PLA was found beneficial for packaging moderate and high respiration rate berries, thus could be commercially feasible for fresh produce industry besides a possible reduction of waste in landfills.