IAEA (DEXAFI) Project Completed

The fourth and final Research Coordination Meeting (RCM) of an IAEA Coordinated Research Project (CRP) on the Development of Electron Beam and X-ray Applications for Food Irradiation (DEXAFI) was held from 7 to 14 April 2021 as a virtual meeting. This CRP involved 14 participating institutions from 12 countries (China, Egypt, France, Indonesia, Japan, South Korea, Pakistan, Poland, Portugal, Thailand, USA, Viet Nam). CRPs aim at establishing an international collaborative research effort on topics of common interest. The overall objective of this CRP was to accelerate the development and facilitate the implementation of practical techniques to irradiate food and agricultural products using electron beam (EB) and X-ray ionizing radiations. The main purpose of the final meeting was to review and evaluate the work in achieving the project objectives. Specific research topics included:

• Proposing new concepts for EB and X-ray machines that can be easily integrated into existing food processing lines. Some progress was made on the construction of a compact low-energy X-ray machine for phytosanitary irradiation (USDA-ARS Hawaii). Independently from the project, new low energy EB and X sources and machines have been developed. An interesting X-ray scanner able to accurately map mass thickness was developed by the participant from China.
• Developing novel pre-packaged foods with improved safety and convenience using EB or X ray irradiation. Products studied included pickled ginger, dried shrimps, fresh pre-cut salads, fresh fruit (mangoes, strawberries, cherry tomatoes) and ready-to-eat meals.
• Determining the lethality of electronic irradiation against food-borne microorganisms for EB and X ray irradiation at energies below 300 keV and compared to conventional gamma irradiation. Previous results were confirmed.
• Re-assessing whether the activation of some food components is of concern when food is irradiated with X-rays at accelerating energies ranging from 5.0 to 7.5 MeV. The French National Science Research Centre (CNRS) refined the Monte Carlo approach and developed a numerical tool that was experimentally validated to predict induced artificial radioactivity from 7.5 MeV X-ray irradiation. It was confirmed that the levels of induced radioactivity are extremely low, transient, and below background levels.
• Improving dosimetry protocols and developing accurate and reliable dosimetry methods and tools for EB and X-ray machines that operate with energies of less than 300 keV and for X-ray machines with energies above 5 MeV (e.g. in the range of 5.0 to 7.5 MeV maximum energy). A comparison conducted by Aerial aimed at measuring the participant’ ability to meet assigned dose values and their ability to measure doses actually applied. The results showed unsatisfactory results for about half of the participants, probably linked to the lack of traceable calibration and the use of inadequate dosimetry systems.

A number of scientific and technical papers were published in various journals in the course of the project. The report of the CRP will be made available in the form of an IAEA TECDOC.