Food irradiation is the process of exposing food to ionizing radiation in order to disinfest, sterilize, or preserve food. It is, like most technology involving ionizing radiation, the subject of some controversy regarding its safety. Irradiation is used on other things as well, such as medical hardware. Largely to avoid consumer fear of the term "radiation", it is often called cold pasteurization or electronic pasteurization to emphasize its similarity to the process of pasteurization.
By irradiating food, depending on the dose, some or all of the microbes and insects present are killed. This prolongs the life of the food in cases where microbial spoilage is the limiting factor in shelf life. Some foods (e.g., herbs and spices) are irradiated at such high doses (5 kilograys or more) that they are partially sterilized. It has also been shown that irradiation can delay the ripening or sprouting 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.
The effects of food irradiation have been studied for over 60 years. Under certain circumstances some research suggests that irradiation forms new chemicals in food, some of which are uniquely radiolytic products. However, the levels of these compounds produced in irradiated foods are deemed too low to present a meaningful risk to consumers. At very high doses, e.g. >6 kilogray, irradiation can reduce the vitamins and other essential nutrients; and negatively impact the flavor, odor and texture of food. At the doses typically used in irradiation treatment of food, e.g. <3.5 kilogray, these changes appear minimal. Independent scientific research on the subject has been extensive leading to endorsement of food irradiation by the US Food and Drug Administration, the United States Department of Agriculture and the U.N. World Health Organization as a safe, effective and desirable process for the production of wholesome food.
Concerns have been expressed by activist groups that irradiation, by killing all bacteria in food, can serve to disguise poor food-handling procedures that could lead to other kinds of contamination. However, processors of irradiated food are subject to all existing regulations, inspections and potential penalties regarding plant safety and sanitization, including fines, recalls and criminal prosecutions.
Others are concerned with the the safety of irradiation plants and accidents that have occurred previously. The three recorded accidents on file at the IAEA in the history of irradiation facilities in the world were suffered by individual employees who entered the radiation chamber disabling all available safety measures. The IAEA and national nuclear commissions followup on all instances to make sure that any risk is further mitigated in future and existing instalations.
Based on the intrinsic inability of radioisotopes used for food irradiation to induce radioactivity into the environment it is imposible for an irradiaiton facility to contaminate the environment with radioactive material. Any problems that might occur are therefore contained in the radiation shield of the installation.
Activist websites frequently quote the unknown cancer risk of radiolitical byproducts as a source of concern Such concern is based mainly on a study published by German scientists Delincee and Pool-Zobel in 1998. Both scientists have repeatedly asked that their work not be misinterpreted in a form that suggests that irradiated food bares any health risks on the consumer.
Labeling laws differ from country to country. In the US as in many other countries labeling regulations require the usage of the Radura symbol at the point of sale together with usage of the word "irradiated" or "treated by irradiation" Food that is processed as an ingredient by a restaurant or food processor is exempt of this requirement.
Widespread food irradiation is credited for some economic benefits. Some foods, particularly fruits and vegetables, are naturally restricted from sale on the global market, unless they are irradiated to prolong quality for transportation. Many countries have bans on importation of foods that may be irradiated.
In the U.S., there is debate fueled mainly by government watch groups like Public Citizen, questioning both the pros and cons of the procedure. Proponents believe that food irradiation results in perfectly wholesome products. They point to many national and international bodies and organizations that endorse food irradiation, mainly due to its overwhelming benefits compared to alternatives available.
There are many alternative methods of food preservation, however none can be so uniformly applied to such a wide range of foods and many involve chemicals with undesireable impact on the product and consumers.
- Irradiation FAQ provided by PHYTOSAN S.A. de C.V. (http://phytosan.com/en/faq.php)
- Irradiation technology provided by PHYTOSAN S.A. de C.V. (http://phytosan.com/en/technology.php)
- Comment by Dr. Henry Linee on an Affidavit misrepresenting the conclusions of his study on unique radiolytical byproducts. (http://www.mnbeef.org/opinion_on_the_expert_affidavit_.htm)