- To treat food with ionizing radiation in order to kill all microorganisms and insects in fruits, cereals, pulses, dried fruits and the like. It also prevents sprouting of roots and tubers. It does not destroy toxins or viruses and may cause chemical changes in the food. Often used to preserve sealed packs of food and to increase the shelf life of perishables. Since no laws govern the labelling of irradiated food it is impossible to know whether it has been treated in this way. Some authorities consider it a dangerous practice.