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. Formerly 5302-43000-035-06T (10/10).
3. Progress Report:
This project supports Objective 2 of the parent project, Evaluate postharvest practices and treatments for table grapes using substances of minimal environmental and dietary risk. Tests to evaluate the use of ozone fumigation to prolong the storage life of fresh grapes were conducted at the San Joaquin Valley Agricultural Sciences Center in Parlier in 2012. Ozone is an allowed substance for use by ‘organic’ growers under the USDA National Organic Program. Application of ozone gas was shown to extend the storage life of table grapes. Under controlled conditions, the ozone treatment during storage was combined in strategies with conventional sulfur dioxide fumigation that was reduced in frequency from once weekly to every two weeks. This strategy resulted in control of postharvest decay that was superior to ozone alone, while reducing sulfur dioxide residues and bleaching injuries to the grapes. This work provides information to add a method to control decay losses in the table grape industry, which produced 99 million boxes worth approximately $1.4 billion in California alone in 2011.