The most recent concern is food irradiation. Irradiation does not make food radioactive. It is yet another method of food preservation. One kilogray is used for irradiating fruits and vegetables while 30 kilograys are used for some dried herbs, spices, and teas.
More radiation is needed for more simple organisms.
Five-hundred rads or five grays over a short period of time is a lethal dose of radiation for most humans. In comparison, a typical chest x-ray produces less than 0.035 rads. Its effectiveness in preservation lies in the chemical alteration of the foods. This alteration destroys insect larvae, bacteria, and other microorgansms in order to delay ripening of perishable foods, retard sprouting of potatoes, annihilate the parasite responsible for trichinosis in pork, and to preserve foods indefinitely, if scaled airtight. In effect, irradiation makes food sterile.