Mark's post today contains this section from Rich Food, Poor Food

"Specifically, irradiation breaks up a food’s DNA, vitamins, minerals, and proteins and creates “free radicals” (atoms, molecules, or ions that contain unpaired electrons and crash into each other, multiplying exponentially), which contribute to many degenerative diseases, including heart disease, dementia, cancer, and cataracts"

Free radicals are highly reactive and do not exist for very long inside a cell...that is how they do their damage. (I'm guessing well under a half a second). Irradiated food would not contain any free radicals. The free radicals that contribute to degenerative diseases are those that are produced inside of a living cell, such as through exposure to radiation or some chemicals.

The authors, I believe, are mixing apples and oranges. Irradiation is an ideal way to effectively "sterilize" food without using additives. I might buy the argument that nutritional quality of irradiated may suffer slightly. Depending on the energy of the radiation used, only the surface of the food would be affected.

Are there any good studies on irradiated food?