Nuclear radiation is able to kill bacteria without significantly changing the food containing the bacteria. So if you seal food in plastic and then radiate it, the food will become sterile and can be stored on a shelf without refrigeration. Unlike canning, however, you do not significantly change the taste or texture of the food when you irradiate it.
The FDA recently approved the irradiation of beef, and the irradiation of chicken has been approved for some time. Irradiation of these meats could prevent many forms of food poisoning. However, many people have a significant problem with the words "nuclear radiation." Therefore, irradiated food is not very common in this country.
For more information on food preservation and related topics, check out the links below.