2019 ASHS Annual Conference

Local fruit and vegetable small acreage production has been steadily expanding in the U.S. Fresh produce is highly perishable and will deteriorate rapidly if appropriate postharvest handling is not practised. However, small acreage producers have limited access to postharvest handling resources like optimum refrigeration conditions and many of the existing tools and techniques are not suitable for small acreage operations. Passive modified atmosphere packaging (MAP) is a relatively inexpensive technique that does not require specialised equipment and has a potential for maintaining the quality and extending the shelf life of fresh produce. Our objective was to determine the effect of passive MAP on the quality and shelf life of locally grown spinach (Spinacia oleracea cv. Corvair) when stored in non-optimum temperatures typical for locally marketed produce. Mature spinach leaves (320 g) were packaged in passive MAP bags, developed using the BreatheWay® technology, and non-MAP produce bags and subsequently stored at 13°C or 20°C. Spinach physical and nutritional quality was evaluated throughout its shelf life in terms of overall visual quality, water loss, surface colour, leaf firmness, electrolyte leakage, chlorophyll fluorescence, antioxidant capacity, and phytochemical content. Spinach that was stored in MAP bags reached headspace equilibrium at approximately 1% Ο₂ and 11% CΟ₂ at 13°C and approximately 3.5% Ο₂ and 6.5% CΟ₂ at 20°C. The main limiting factors for the control treatment, for both storage temperatures, was accelerated yellowing and water loss, while for the MAP treatment decay due to condensation limited shelf life. MAP packaging only slightly improved the visual quality of spinach stored at 21°C but resulted in a shelf life extension of 2 days at 13°C. There were no differences in antioxidant capacity and total phenolic content between the treatments at both temperatures throughout shelf life. Passive MAP can be an effective tool for extending the shelf life and maintaining the quality of locally produced spinach. Using a film with increased water vapour transmission rate (WVRT) could potentially mitigate the condensation issues of the MAP packaging and further increase the shelf life of spinach stored at non-optimum temperatures.