Application of Gaseous Ozone to Enhance Quality and Microbiological Safety of Strawberries

Ozonation represents one of the most promising non-thermal methods for enhancing the quality and storage safety of fresh fruits. In this study, the effects of gaseous ozone fumigation at different concentrations (10 and 50 ppm) and exposure times (10 and 20 min) on selected physicochemical and microbiological properties of strawberries during 7-day refrigerated storage were evaluated. Water content, mechanical properties, the profile and content of bioactive compounds (polyphenols, vitamin C), and antioxidant activity, as well as microbial counts and the dynamics of CO₂ and ethylene production, were assessed. The results demonstrated that ozonation reduced water loss and slowed metabolic processes and fruit ripening, as indicated by lower CO₂ and ethylene levels compared to the control. The application of ozone, particularly at the higher dose (50 ppm), contributed to maintaining higher vitamin C content and antioxidant activity and significantly reduced the number of mesophilic bacteria, yeasts, and molds, achieving reductions of approximately 1.86 log and 0.97 log on Day 7 compared with the untreated control, respectively. No adverse effects of ozonation on the mechanical properties of the fruit were observed. The findings confirm the relevance of gaseous ozone as a quality-enhancing elicitor and an effective tool for reducing microbiological contamination of fresh strawberries without compromising their properties.