2009 Annual Report 1a.Objectives (from AD-416) Evaluate benefits and risks of using ozone to control postharvest decay of table grapes. 1b.Approach (from AD-416) Fumigate with ozone under laboratory and commercial conditions to establish effective rates. Documents Trust with California Table Grape Commission. Log 38919 3.Progress Report Postharvest quality is an important aspect of table grapes marketing, but the influence of ozone gas during storage remains unclear. Ozone, a well-known biocide gas, reduced postharvest decay by approximately 50% when applied in very high concentrations for one hour before cold storage. The use of constant low concentrations of ozone gas will be determined using equipment that will precisely control its concentration during the storage of packaged grapes. The influence of the gas on the severity of postharvest decay losses and its ability to penetrate commercial packaging will be determined. Cooperator activity has been monitored by the use of technical meetings, visits to the laboratory, and telephone conversations.