Microwaves work by exciting molecules in water, causing them to heat up. Electron beams work by destroying DNA in the cells of its target, and also destroy DNA in the food that is an incidental recipient of the radiation. Electron beams can actually be used in conjunction with metal to produce x-rays. Not so with microwaves. Electron-beam irradiation causes all the same harmful effects in food as gamma irradiation, and there is evidence that is can actually induce traces of radioactivity in the food.
Irradiation compounds vitamin loss from cooking.
Approved by the Twelfth Health Assembly, May 28, 1959. Resolution WHA 12.40 5. Accelerator Safety Self-Study, April 1999 10. Ibid., p29 11.