Effect of low SO2 postharvest treatment on quality parameters of ‘Italia’ table grape during prolonged cold storage

Table grape is a non-climacteric fruit with a low rate of physiological activity, very sensitive to water loss and fungal infection (Botrytis cinerea) during postharvest handling and cold storage. Gray mold is the most aggressive postharvest disease, because of its ability to develop at low temperatures, for that reason, it is standard practice to fumigate with sulfur dioxide (SO2) immediately after packing. ‘Italia’ table grape boxes were stored at 2°C for 4 months in a storage room with low concentrations of SO2 (0.20%) to extend their postharvest shelf life. Every 15 days, a sample of ‘Italia’ table grapes boxes was moved to 20°C for 3 days for the shelf life simulation. During storage, table grapes clusters were analyzed in terms of firmness, weight loss, total soluble solids content, titratable acidity, rachis and berry decay. A sample of ‘Italia’ table grapes was stored at 1°C without SO2 treatment for control. ‘Italia’ table grapes clusters stored at 2°C and treated with low SO2 (0.20%) showed good postharvest performances until 3 months of cold storage in terms of firmness, weight loss, total soluble solids content and titratable acidity. Moreover, rachis and berry decays were inhibited by low SO2 treatment.