Submitted to: Journal of Food Processing and Preservation
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/24/2008
Publication Date: 4/15/2009
Citation: Follett, P.A., Weinert, E.D. 2009. Comparative radiation dose mapping of single fruit type and mixed tropical fruit boxes for export from Hawaii. Journal of Food Processing and Preservation. 33: 231-244 Interpretive Summary: Present regulatory guidelines for applying quarantine treatments are for single commodities only. The advent of generic irradiation treatments aimed at broad pest groups without respect to commodity prompted the present study to determine if mixed fruits could be irradiated using single fruit protocols while meeting the technical objectives of the treatment. Dose mapping of single and mixed fruit boxes in the present study suggested that fruit mixtures can be irradiated using the same protocols developed for single fruits. Standard dose mapping should be conducted for each fruit mixture type to effectively apply the irradiation treatment and meet the technical objectives of the treatment. This could lead to export approvals for value-added mixed fruit gift boxes or other products which would diversify revenue for the tropical fruit industry.
Technical Abstract: Quarantine treatment protocols to disinfest fresh agricultural commodities of quarantine pests are traditionally developed for and applied to single commodities. Recently, generic radiation treatments were approved in the USA to control insect pests irrespective of commodity. Approved generic doses are150 Gy for any tephritid fruit fly and 400 Gy for all other insects except the pupa and adult stages of Lepidoptera. Theoretically, generic radiation doses could be applied to a mixture of fruits provided the required minimum absorbed dose to control the pests is achieved and the 1 kGy limit is not surpassed. Dose mapping studies were conducted to compare dose variation during radiation treatment at 400 Gy of single and mixed fruits packed in boxes. Tests included papaya, mango, banana, rambutan, longan, dragon fruit, and various combinations of these fruits. When radiation was applied to a single box containing one type of fruit or a mixture of two or three fruit types, measured doses were sometimes higher in the mixture. Irradiation of a simulated commercial load of 12 boxes resulted in no significant difference between single fruit boxes and mixed fruit boxes. In all experiments the technical objectives of radiation treatment were met, meaning the minimum required dose of 400 Gy was achieved without exceeding the maximum allowable dose of 1 kGy. Irradiation of fruit mixtures using generic doses should be acceptable and could lead to export approvals for value-added products which would help diversify revenues for the agriculture industry.