Submitted to: Journal of Radiation Physics and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2002
Publication Date: 2/13/2003
Citation: Gregoire, O., Cleland, M.R., Mittendorfer, J., Dababneh, S., Ehlermann, D.A., Fan, X., Kappeler, F., Logar, J., Meissner, J., Thayer, D.W. 2003. Safety food irradiation with high energy x-rays: theoretical expectations and experimental evidence. Journal of Radiation Physics and Chemistry. 67(2):169-183. Interpretive Summary: Irradiation of food with X-rays is presently limited by the U.S. Food and Drug Administration to a maximum energy of 5 million electron volts (MeV) primarily because information was lacking to establish the radiological safety of the process using more efficient energies such as 7.5 MeV. The concern of the regulatory agencies was that theoretically high energy X-rays could generate neutrons and result in the food becoming slightly radioactive. The process was evaluated with two types of electron accelerators delivering electrons with a narrow and a broad energy spectrum in which a meat was irradiated with 7.5 MeV X-rays to a maximum dose of 15 kGy, twice the maximum dose allowed by the U.S. FDA. The measured activities and theoretical estimates were in the same order of magnitude and were less than the natural radioactivity of the meat. The conclusion is that irradiation of food with X-rays generated by 7.5 MeV electrons can be regarded as safe. Use of 7.5 MeV X-rays for food irradiation will significantly decrease the cost of the process and thus improve the overall safety of our food supply benefiting the consumer.
Technical Abstract: The radiological safety of red meat irradiated with 7.5 MeV X-rays (bremsstrahlung) has been investigated theoretically and verified by dedicated experiments. Samples of meat and meat ash were located in a large volume of fresh meat at the position of the highest neutron fluence and irradiated to 15 kGy, twice the maximum dose allowed by the US FDA for meat irradiation. In order to evaluate the safety of treatment with any kind of electron accelerators, 2 experiments have been performed with different accelerators delivering electrons with a narrow and a broad energy spread. The measured activities and theoretical estimates are in the same order of magnitude. An evaluation of the corresponding radiation exposure from ingestion of the irradiated product has been compared to natural background radiation and the extent of possible biological effects has been considered. The paper concludes that food irradiation with X-rays from 7.5 MeV electrons, even with a broad energy spectrum, can be regarded safe from the standpoint of public health.