Postharvest irradiation for market access of fresh produce

Authors: Follett, Peter

Submitted to: United States-Japan Cooperative Program in Natural Resources (UJNR)
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2017
Publication Date: 11/2/2017
Citation: Follett, P.A. 2017. Postharvest irradiation for market access of fresh produce. United States-Japan Cooperative Program in Natural Resources (UJNR). November 11-15, 2017 Hiroshima Japan.

Interpretive Summary: Phytosanitary treatments such as irradiation disinfest host commodities of quarantine insect pests before they are exported to areas where the pests do not occur, and are often the simplest approach to overcome regulatory trade barriers and gain market access. Irradiation is a versatile technology to disinfest fresh and durable agricultural commodities of quarantine pests. Irradiation is broadly effective against insects and mites, cost competitive with other disinfestation methods such as chemical fumigation, and fast. Irradiation generally does not significantly reduce commodity quality at the doses used to control insect pests, and may extend shelf-life. Additionally, irradiation can be applied to the commodity after packaging. In 2006, USDA approved first-ever generic irradiation treatments against broad groups of insects. The availability of generic radiation treatments has stimulated worldwide interest in phytosanitary uses of this technology. India, Pakistan, South Africa, Thailand, Vietnam, Peru, and Australia are exporting a variety of tropical fruits to the United States, and volumes have grown steadily since the approval of generic doses. The main fruits include mangos (India, Pakistan, Mexico, Australia), guava (Mexico), persimmons (South Africa), mangosteen (Thailand), and dragon fruit, longan, and rambutan (Vietnam). Australia is exporting irradiated mangos, papayas and lychee to New Zealand using generic treatments as well. Vietnam is expanding exports beyond the United States. Hawaii uses the generic radiation treatments to export 5-6 tonnes of tropical fruits and vegetables to the United States mainland annually, with sweet potato as the main export. Overall, more than 20,000 tonnes per year of irradiated fresh produce is being sold at retail markets worldwide, much of it over several years, indicating that there is a market for irradiated produce. Most of the produce at this point has been sold in the USA and New Zealand. The recent growth in phytosanitary uses of irradiation is unprecedented in the history of food irradiation-addressing the few remaining issues will help promote continued expansion.

Technical Abstract: The United States Food and Drug Administration has approved radiation doses up to 1000Gy (1kGy) for preservation and disinfestation of fresh fruits and vegetables. Disinfestation means controlling any arthropod pests infesting the commodity, particularly insects. The source of ionizing radiation can be gamma rays produced by radionuclides (60Co or 137Cs), or electrons or x-rays generated from a machine sources operated within certain energy limits. Ionizing radiation breaks chemical bonds within DNA and other biomolecules, thereby disrupting normal cellular function in the infesting insect. Phytosanitary treatments such as irradiation disinfest host commodities of quarantine insect pests before they are exported to areas where the pests do not occur, and are often the simplest approach to overcome regulatory trade barriers and gain market access. Several issues present barriers to the wider use of phytosanitary irradiation. Because irradiation is characterized as a food additive rather than a process, its use must be disclosed on a label. The labelling requirement may be a drawback for retailers that believe consumers are reluctant to buy irradiated food. The 1kGy limit is archaic and reduces the efficiency of applying the treatment. USDA APHIS has placed limits on the use of modified atmosphere packaging with irradiation, which disrupts commercial practices that ensure superior commodity quality. The limited number of countries that have approved phytosanitary uses of irradiation is hampering broader adoption due to closed markets. Nonetheless, the recent growth in phytosanitary uses of irradiation is unprecedented in the history of food irradiation-addressing the few remaining issues will help promote continued expansion.