Food irradiation is the process of treating food with a specific dosage of ionizing radiation.[1] The major effect of irradiation is to generate short-lived and transient radicals (e.g. the hydroxy radical, the hydrogen atom and solvated electrons) that in turn damage DNA and intercellular structures. The target organism ceases all processes related to maturation or reproduction. At high enough doses the target organism does not survive.[1] This treatment slows or halts spoilage by retarding enzymic action or destroying microorganisms and it can also inactivate foodborne pathogenic organisms (reducing the risk of food borne illness). Further applications include sprout inhibition, delay of ripening, increase of juice yield, and improvement of re-hydration. Irradiation is also used to prevent the spread of invasive insect species that could be associated with fresh produce (e.g. fruit fly pests).
Ionizing radiation affects cells and microorganisms by damaging their DNA beyond its ability to repair, breaking down cell membranes and interrupting enzymic pathways. Organisms can no longer successfully continue the process of cell division. Irradiated food does not become radioactive, as the particles that transmit radiation are not themselves radioactive.
Food irradiation is currently permitted by over 50 countries, and the volume of food treated is estimated to exceed 500,000 metric tons annually worldwide; however, the extent of clearances is varying significantly, from a single food category (dried herbs, spices and vegetable seasonings) in Austria, Germany, and many other countries of the European Union to any food in Brazil.[2][3][4][5][6]
Still there is some controversy in the application of irradiation possibly due to it being confused with radioactive contamination and an imputed association with the nuclear industry, and also perhaps because people think that chemical changes will be different than the chemical changes due to heating food (as ionizing radiation produces a higher energy transfer per collision than conventional radiant heat). However, research has found that most, if not all, of the substances formed in irradiated food are also found in food that has been subjected to other processing treatments and are not exclusively formed by irradiation. Furthermore, the quantities in which they occur in irradiated food are not significantly higher than those being formed in heat treatments.[7][8][9][10]
Irradiation is a more general term of the exposure of materials to radiation to achieve a technical goal (in this context "ionizing radiation" is implied). As such it is also used on non-food items, such as medical devices, plastics, tubes for gas pipelines, hoses for floor heating, shrink-foils for food packaging, automobile parts, wires and cables (isolation), tires, and even gemstones.
