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Some forms of radiation will not induce objects to become radioactive. One example of this is gamma rays. Gamma rays are very short wavelength electromagnetic radiation, and are extremely energetic and hostile to life. If used at the correct doses, they can be used to sterilize objects, and this technique is used in the production of medical instruments and disposables, such as syringes as well as in the disinfestation and sterilization of food.
By irradiating the food, some or all microbes and insects in it are killed (depending on dose). This prolongs the life of the food greatly, but can have the disadvantage of killing beneficial microbes. Other foods (e.g., herbs and spices) are irradiated at such high doses (5 kilo- grays or more) that they are partially sterilized. It has also been claimed that irradiation can delay the ripening of fruits and vegetables and replace the need for pesticides.
The United Nations Environmental Program passed The Montreal Protocol on Substances That Deplete the Ozone Layer banning amongst other substances all non-critical uses of methyl bromide, the most common fumigant for post harvest quarantine treatment of fruit. Although in theory still permitted for quarantine applications, prices of the fumigant have increased dramatically as a consequence. Irradiation is largely recognized by the international community as a legitimate replacement for such fumigants and in consequence many large agricultural nations of the world are currently building irradiation facilities for fresh fruit.
At the present time the implications surrounding the irradiation of food are still not fully understood. Irradiation forms new chemicals in food, some have never been seen before in nature, while others are known or suspected to cause cancer and birth defects. Irradiation also destroys vitamins and other essential nutrients; and corrupts the flavor, odor and texture of food. Independent scientific research on the subject has been slow to emerge.
There are concerns that irradiation, by killing all bacteria in food, can serve to disguise very poor food-handling procedures that could lead to other kinds of contamination.
Others are concerned with the use of radiation, and use of nuclear byproducts, the safety of irradiation plants and accidents that have occurred previously.
Labeling laws differ from country to country. Irradiated foods may be labeled with a number of ephamistic terms used not to alarm consumers by such as "cold pasteurization" and "electronically pasteurised".
Irradiated foods allow fruits and vegetables to pushed into the global market where previously their distribution was naturally restricted. Many countries restrict the foods which may be irradiated.
Proponants claim that food irradiation results in perfectly wholesome food and claim almost all national and international bodies and organizations endorse the procedure due to its overwhelming benefits compared to alternatives available. Proponants say that controversy is mainly kept up by alarmist groups like Public Citizen in the U.S. with little scientific or factual merit.
There are many alternative methods of food preservation, however none can be so uniformly applied to such a wide range of foods.
See also: Deinococcus radiodurans
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