Before fresh fruits and vegetables trek across oceans and borders along international trade routes and to the aisles of neighbourhood grocers, they may be treated to eliminate, inactivate or sterilize pests. This highly regulated practice of disinfestation typically involves phytosanitary, or post-harvest, treatments to stop potentially pesky hitchhikers - and is increasingly done using irradiation rather than chemicals.
What are phytosanitary treatments?
Phytosanitary treatments are processes that mitigate biosecurity risks - pests and other non-native organisms - from being introduced and established in pest-free areas. Cold, heat and chemical applications are the most used phytosanitary treatments. "Heat treatment, irradiation and fumigation are conducted before shipment or upon arrival and are usually done in a matter of hours or less," said Scott Myers, Assistant Director of Otis Laboratory at the US Department of Agriculture (USDA).
With increasing restrictions placed on the use of chemical fumigants by importing countries, the use of irradiation as phytosanitary treatment is increasing around the world. It uses ionizing radiation to render pests infertile and "has the benefit of a short treatment time and can maintain the quality of perishable or delicate commodities, such as berries, guavas and figs," Myers said.
Phytosanitary treatment implementation relies on science-based agreements between trade partners, a process that can take years to establish. To help trade and health officials harmonize treatments, as well as understand the role of irradiation as a harmless and environmentally friendly phytosanitary treatment option, the IAEA, in cooperation with the Food and Agriculture Organization of the United Nations (FAO), established a partnership with the USDA in 2010. "The evaluation of phytosanitary treatment efficacy and the proposal of new treatment schedules require access to a large number of colonized insect pest species and specimens, proper equipment and qualified human resources to be conducted," said Vanessa Dias, an entomologist at the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture
