Text Box: 11:10 AM Text Box: MICROBIOLOGY Text Box: Shelf-life Extension of Strawberries Using Ozone-based Combination Treatments Text Box: Mustafa Vurma and Dr. Yousef Text Box: Strawberries are popular but highly perishable fruits. Fungi are commonly associated with the quality deterioration of strawberries, resulting in significant economic losses. Post-harvest treatments for strawberries are limited, but gaseous sanitizers are potentially useful in improving product shelf-life and safety. The objective of this study was to assess the feasibility of using ozone (O3), carbon dioxide (CO2), or their combinations, for reducing natural microbiota, and extending the shelf-life of strawberries. A gaseous treatment setup, consisting of an ozone generator and a 300-liter chamber equipped with an O3 monitor and O3 and CO2 inlet/outlet ports, was used. Strawberries (~1lb), in their original plastic container, were treated with O3, CO2, or their combination, for 0, 1, 2, and 4 h. In O3+CO2 treatments, CO2 was fed in the chamber for 5 min at 100 scfh flow rate. The concentration of O3 was maintained at 10 ppm (vol/vol in O2) during each treatment. Control and treated strawberries were evaluated for total aerobic-mesophilic, and yeast-mold counts, as well as overall appearance during storage at 4 and 20°C. The O3+CO2 combination treatments were the most effective in delaying mold growth and quality deterioration of the strawberries. When samples were treated with O3+CO2 for 4 h and stored at 4°C, the initiation of visual mold appearance was delayed until the 16th day of storage; an 8-day extension compared to untreated samples. The differences between combination and control treatments in yeast-mold counts were 1.1 log CFU/g immediately after the treatment and approximately 1.8 log CFU/g after 15 days of storage. The overall difference in total aerobic-mesophilic counts between treated and untreated samples was approximately 1.2 log CFU/g throughout the storage period. In conclusion, treating fresh strawberries with O3+CO2 combination is a feasible technology for extending the shelf-life, and potentially improving the safety, of this perishable fruit.