What Ben said, with one clarification. Radiation sterilization is what he described. This almost "cooks" the foods and is akin to, say canning.

On the other hand, fresh foods like ground beef, strawberries, etc. can be radiation pasteurized which extends the fresh shelf life and kills the real nasties like e-coli but not the normal spoilage bateria that starts to stink and let you know the food is old.

Even at the much lower doses needed for pasteurization, it is still an expensive process. I worked for a company that was trying to make it more economical but the industry does not encourage innovation and they were basically squashed.

Sure, you can be on a first name basis with the cow, he farmer, the butcher, the cook, and so on, but it only takes one little mistake or lapse of discipline to contaminate the food. In God we trust, all others we irradiate.

You can find some irradiated foods in the store, look for the Radura symbol