<OL> <LI> Continue a project to evaluate ozone for use on fresh fruit and nuts to control pests of the commodities following harvest. <LI>Acquire and fabricate test equipment, develop ozone detection methodology and establish the efficacy of various dosages of ozone to eliminate pathogens from several commodities. <LI>Determine if ozone has potential to replace current methodology in postharvest treatments. <LI>Establish the benefits and disadvantages of using ozone for postharvest treatments.
APPROACH: Laboratory bench-scale and semi-commercial scale equipment to generate and to apply ozone in water or ozone in air will be fabricated or acquired. The influence of many practical and environmental parameters, such as the duration of contact, temperature, and humidity, on ozone toxicity to a variety of food-borne spoilage pathogens will be determined in series of factorial bench-scale experiments. The tolerance of fresh fruits to ozone applied at rates that control these fungi will be determined. Promising treatments, namely those where control of spoilage organisms occur without significant injury to the treated commodities, will be candidates for progressively larger experiments and technology transfer activities. We will rigorously evaluate these applications in semi-commercial scale tests at our facility and seek commercial food processors to collaborate in trials in operating plants. Documents Trust with UC-Davis Log 17261. Formerly 5302-43000-025-02R (10/02).
PROGRESS: 2000/01 TO 2004/12<BR>
This report serves to document research conducted under a reimbursable trust agreement between ARS and the University of California at Davis/California Energy Commission on the subject of the development and evaluation of ozone applications in agriculture. This project is related to the in-house project (CRIS 5302-43000-029-00D) to develop safe alternatives to synthetic fungicides. Ozone levels in the ozonated room and inside the typical citrus industry packages were monitored and ozone penetration in each type of package was calculated. Ozone penetration was strongly dependent on the vented area of each type of package, and while it was very low through fiberboard cartons or polyethylene bags (9-17% of the room ozone dose), it was acceptable only into hard plastic, returnable plastic containers with large vents (82% of the room ozone dose). Since the gas was not able to penetrate through fiberboard cartons or plastic bags, which are commonly used for commercial packaging of not only citrus but a large variety of fruits and vegetables, the suitability of ozone gas exposure during storage as an alternative or complementary treatment for the management of postharvest diseases of fresh produce is limited.