I was listening to a lecture yesterday given by the discoverer of the West Nile virus, and he mentioned a topic that I have discussed before: The fact that irradiation of food would greatly reduce food-transmitted illness.
I would like to expand on that topic here, discussing it both as a physicist and as a physician. It is important to realize that gamma radiation at the energies we would employ canNOT make the food radioactive.
There are three types of radiation: alpha rays,. or helium nuclei (two protons plus two neutrons), beta rays, or electrons, and gamma rays, or photons, which we know as visible radiation, infrared radiation, ultraviolet radiation, microwave radiation, radio waves, television waves, or xrays (the label varies depending on the wavelength and energy of the radiation, but they are all photons, or packets of energy). At energies below several Mev (and xrays are in the Kev range, or 1,000 times less energetic) a nucleus cannot be made radioactive. All that Kev radiation can do is to disrupt the nucleus of the cell and fragment its DNA, thereby either killing the cell or rendering it incapable of reproducing. But the food we eat is already dead or dying, and disrupting the nuclei of a leaf of lettuce will not kill it twice over---dead is dead. And the vegetable nucleus cannot absorb the gamma radiation and release it when we eat it; such a process is impossible by the laws of physics, which are much more accurate and precise than the laws of medicine.
The people who got harmed by gamma radiation were people directly exposed to high energy Xrays, such as those at Hiroshima and Nagasaki, as well as many of the people around Chernobyl and Fukushima. The irradiation of the food would take place in processing plants, far away from us, and in a lead-lined shielded room. The radiation would kill viruses (no hepatitis transmitted by the lettuce you eat) bacteria, (no E. Coli from the hamburgers you eat), and parasites (no tapeworm or trichinosis from the ham you eat).
As a public health measure, this process is inexpensive and tremendously protective, but there is an irrational fear of "radiation". Apparently we would rather risk becoming ill by ingesting possibly contaminated food, than expose ourselves to irradiated food. I was also reminded that MRI, or Magnetic Radiation Imaging was initially called NMR, for Nuclear Magnetic Resonance, which is an accurate label of the physics involved, but the "powers that be" pandered to the fear of the word "radiation" by changing its name.