Effect of preharvest salt treatment and ozone low concentration on postharvest decay peaches

To meet the increasing demand for safe and high quality fresh peaches and the recent food safety regulations is important to embrace a holistic approach combining preand postharvest practices in view of attaining maximum quality and satisfaction at the consumer level. Modern sanitation techniques relying on application of physical methods and/or Generally Recognized As Safe (GRAS) compounds are desired for reducing microbiological spoilage. Ozone has attracted considerable commercial interest, especially because it does not leave any residue on produce and is accepted by many organic grower organizations. The activity of preharvest application of 1% calcium chloride and Fortisol (Citrosol, Valencia, Spain) in combination with postharvest O3 (150 ppb) supply on postharvest rots of peaches cv Notarangelo is reported. Water and fenhexamid (500g/ha a.i.) were used as untreated and chemical control, respectively. Three days after in the field treatment, fruits were harvested and cold-stored for 15 days (3±2°C, 92±5% RH) in presence of conventional or ozonized atmosphere. At the end of storage in both storage conditions no rotted fruits were observed. After three days of storage at 20°C shelf-life, calcium chloride and Fortisol, compared to the untreated control, resulted in a reduction of rots of 34% and 70%, respectively, instead in presence of O3 the reduction was 25 and 48%. Furthermore, in ozonized atmosphere the weight losses was significantly lower as compared to the conventional atmosphere and, consequently, fruits on the whole showed a more fresh appearance. Ozone influenced microbial epiphytic population, being bacteria and filamentous fungi reduced and yeasts increased at the end of cold storage. In addition, the activities of beta-1,3-glucanase, peroxidase, chitinase, and peroxidase were increased in salt treated peach fruits. The combined application of salts and O3 could be an acceptable strategy for preserving postharvest quality of peach fruits.