Food irradiation

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Cobalt-60 irradiation facility is used to test irradiation as a tool to ensure food safety.
The international Radura logo, used to show a food has been treated with ionizing radiation.
A portable, trailer-mounted food irradiation machine, circa 1968

Food irradiation is the process of exposing foodstuffs to ionizing radiation. Ionizing radiation is energy that can be transmitted without direct contact (radiation) capable of freeing electrons from their atomic bonds (ionization) in the targeted food.[1][1][2] This treatment is used to preserve food, reduce the risk of food borne illness, prevent the spread of invasive pests, and delay or eliminate sprouting or ripening. Irradiated food does not become radioactive. The radiation can be emitted by a radioactive substance or generated electrically.

Irradiation is also used for non-food applications, such as medical devices.[3]

Although consumer perception of foods treated with irradiation is more negative than those processed by other means,[4] a large amount of independent research has confirmed irradiation to be safe.[5][6][7][8][9] One family of chemicals (2ACB's) are uniquely formed by irradiation (unique radiolytic products), and this product is nontoxic. When irradiating food, all other chemicals occur in a lower or comparable frequency to other food processing techniques.[6][7][10][11]

Food irradiation is permitted by over 60 countries, with about 500,000 metric tons of food annually processed worldwide.[12] The regulations that dictate how food is to be irradiated, as well as the food allowed to be irradiated, vary greatly from country to country. In Austria, Germany, and many other countries of the European Union only dried herbs, spices, and seasonings can be processed with irradiation and only at a specific dose, while in Brazil all foods are allowed at any dose.[13][14][15][16][17]


Irradiation is used to reduce or eliminate the risk of food born illnesses, prevent or slow down spoilage, arrest maturation or sprouting and as a treatment against pests. Depending on the dose, some or all of the pathogenic organisms, microorganisms, bacteria, and viruses present are destroyed, slowed down, or rendered incapable of reproduction. Most foods irradiated are treated to doses that do not completely sterilize the product, but which significantly reduces the microbial load. In this respect it is similar to pasteurization. Some foods can tolerate irradiation at sufficient doses to ensure that the product is completely sterilized but this is rare (rations for astronauts, special diets for hospital patients). Irradiation also reduces the populations of spoilage microorganisms and because pre-packed food can be irradiated, the packaging prevents recontamination into the final product.[1]

Irradiation is used to reduce post harvest losses. It reduces populations of spoilage micro-organisms in the food and can slow down the speed at which enzymes change the food and therefore slows spoilage, ripening, and inhibits sprouting (e.g. of potato, onion and garlic).[18]

Irradiation cannot revert spoiled or over ripened food to a fresh state. If this food was processed by irradiation, further spoilage would cease and ripening would slow down, yet the irradiation would not destroy the toxins or repair the texture, color, or taste of the food.[18]

Food is also irradiated to prevent the spread of invasive pest species through trade in fresh vegetables and fruits, either within countries (e.g. fruit fly in Australia) or trade across international boundaries (e.g. prevent the spread of fruit fly from Mexico to USA). The pests are sterilized when the food is treated by low doses of irradiation. In general the higher doses required to destroy pests such as insects, mealybugs, mites, moths and butterflies either affect the look or taste or cannot be tolerated by fresh produce.[19] Low dosage treatments (less than 1000 gray) enables trade across quarantine boundaries[20] and may also help reduce spoilage.

Public perception[edit]

Irradiation has been approved by many countries, for example in the US the FDA has approved food irradiation for over 50 years. However, in the past decade the major growth area is for fruits and vegetables that are irradiated to prevent the spread of pests, such as insects, that could be transported to new habitats through trade in fresh produce and which could significantly affect agricultural production and the environment were they to establish themselves. This "phytosanitary irradiation"[21] aims to render any hitch-hiking pest incapable of breeding. Sales of fresh produce so treated do not seem to be affected by the fact that the product is irradiated and clearly labeled as such. This challenges the received wisdom that sales are affected by negative consumer perception and has led some experts to argue that the commercialization of irradiated food is more affected by food retailers fearing adverse public reaction than by the actual reaction of customers.[22] In the early 2000s in the US, irradiated meat was common at some grocery stores, but because of lack of consumer demand it is no longer common. Because consumer demand for irradiated food is low, reducing the spoilage between manufacture and consumer purchase and reducing the risk of food borne illness is currently not sufficient incentive for most manufactures to supplement their process with irradiation.[3] Nevertheless, food irradiation does take place commercially and volumes are in general increasing at a slow rate, even in the European Union where all member countries allow the irradiation of dried herbs spices and vegetable seasonings but only a few allow other foods to be sold as irradiated.[23]

There is now sufficient experience to show that when labeled irradiated food is offered for retail sale, consumers buy it and re-purchase it, indicating that irradiated foods may be marketed profitably and without risk to reputation.[24] It is however, widely believed that consumer perception of foods treated with irradiation is more negative than those processed by other means, although many of these consumer surveys are dated [4] and some industry studies indicate the number of consumers concerned about the safety of irradiated food decreased between 1985 and 1995 to levels comparable to those of people concerned about food additives and preservatives.[25] "These irradiated foods are not less safe than others," Dr. Tarantino said, "and the doses are effective in reducing the level of disease-causing micro-organisms." "People think the product is radioactive," said Harlan Clemmons, president of Sadex, a food irradiation company based in Sioux City, Iowa.[26] Because of these concerns and the increased cost of irradiated foods, there is not a widespread public demand for the irradiation of foods for human consumption.[3]


Irradiation reduces the risk of infection and spoilage, does not make food radioactive, and the food is shown to be safe, but it does cause chemical reactions that alter the food and therefore alters the chemical makeup, nutritional content, and the sensory qualities of the food.[3] Some of the potential secondary impacts of irradiation are hypothetical, while others are demonstrated. These effects include cumulative impacts to pathogens, people, and the environment due to the reduction of food quality, the transpiration and storage of radioactive goods, and destruction of pathogens, changes in the way we relate to food and how irradiation changes the food production and shipping industries.

Immediate effects[edit]

The radiation source supplies energetic particles or waves. As these waves/particles pass through a target material they collide with other particles. Around the sites of these collisions chemical bonds are broken, creating short lived radicals (e.g. the hydroxyl radical, the hydrogen atom and solvated electrons). These radicals cause further chemical changes by bonding with and or stripping particles from nearby molecules. When collisions damage DNA or RNA, effective reproduction becomes unlikely, also when collisions occur in cells, cell division is often suppressed.[1]

Irradiation (within the accepted energy limits, as 10 MeV for electrons, 5 MeV for X-rays [US 7.5 MeV] and gamma rays from Cobalt-60) can not make food radioactive, but it does produce radiolytic products, and free radicals in the food. A few of these products are unique, but not considered dangerous.[27]

Irradiation can also alter the nutritional content and flavor of foods, much like cooking.[27] The scale of these chemical changes is not unique. Cooking, smoking, salting, and other less novel techniques, cause the food to be altered so drastically that its original nature is almost unrecognizable, and must be called by a different name. Storage of food also causes dramatic chemical changes, ones that eventually lead to deterioration and spoilage.[28]


A major concern is that irradiation might cause chemical changes that are harmful to the consumer. Several national expert groups and two international expert groups evaluated the available data and concluded that any food at any dose is wholesome and safe to consume as long as it remains palatable and maintains its technical properties (e.g. feel, texture, or color).[6][7]

Irradiated food does not become radioactive, just as an object exposed to light does not start producing light. Radioactivity is the ability of a substance to emit high energy particles. When particles hit the target materials they may free other highly energetic particles. This ends shortly after the end of the exposure, much like objects stop reflecting light when the source is turned off and warm objects emit heat until they cool down but do not continue to produce their own heat. To modify a material so that it keeps emitting radiation (induce radiation) the atomic cores (nucleus) of the atoms in the target material must be modified.

It is impossible for food irradiators to induce radiation into a product. Irradiators emit electrons or photons and the radiation is intrinsically radiated at precisely known strengths (wavelengths for photons, and speeds for electrons). These radiated particles at these strengths can never be strong enough to modify the nucleus of the targeted atom in the food, regardless of how many particles hit the target material, and radioactivity can not be induced without modifying the nucleus.[27]

Chemical changes[edit]

Compounds known as free radicals form when food is irradiated. Most of these are oxidizers (i.e., accept electrons) and some react very strongly. According to the free-radical theory of aging excessive amounts of these free radicals can lead to cell injury and cell death, which may contribute to many diseases.[29] However, this generally relates to the free radicals generated in the body, not the free radicals consumed by the individual, as much of these are destroyed in the digestive process.

When fatty acids are irradiated, a family of compounds called 2-alkylcyclobutanones (2-ACBs) are produced. These are thought to be unique radiolytic products. Most of the substances found in irradiated food are also found in food that has been subjected to other food processing treatments, and are therefore not unique. Furthermore, the quantities in which they occur in irradiated food are lower or similar to the quantities formed in heat treatments.[6][7][10][11]

The radiation doses to cause toxic changes are much higher than the doses used to during irradiation, and taking into account the presence of 2-ACBs along with what is known of free radicals, these results lead to the conclusion that there is no significant risk from radiolytic products.[5]

Food quality[edit]

Ionizing radiation can change food quality but in general very high levels of radiation treatment (many thousands of gray) are necessary to adversely change nutritional content, as well as the sensory qualities (taste, appearance, and texture). Irradiation to the doses used commercially to treat food have very little negative impact on the sensory qualities and nutrient content in foods. When irradiation is used to maintain food quality for a longer period of time (improve the shelf stability of some sensory qualities and nutrients) the improvement means that more consumers have access to the original taste, texture, appearance, and nutrients.[30][31][32] The changes in quality and nutrition depend on the degree of treatment and may vary greatly from food to food.[18]

There has been low level gamma irradiation that has been attempted on arugula,[33] spinach,[34] cauliflower,[35] ash gourd,[36] bamboo shoots,[37] coriander, parsley, and watercress.[38] There has been limited information, however, regarding the physical, chemical and/or bioactive properties and the shelf life on these minimally processed vegetables.[32]

Because the nutritional content changes after irradiation and because of the loss of probiotics food advocacy groups consider labeling irradiated food raw as misleading.[39] However, the degradation of vitamins caused by irradiation is similar or even less than the loss caused by other food preservation processes. Other processes like chilling, freezing, drying, and heating also result in some vitamin loss.[18]

The changes in the flavor of fatty foods like meats, nuts and oils are sometimes noticeable, while the changes in lean products like fruits and vegetables are less so. Some studies by the irradiation industry show that for some properly treated fruits and vegetables irradiation is seen by consumers to improve the sensory qualities of the product compared to untreated fruits and vegetables.[18]

Quality Impact on Minimally Processed Vegetables[edit]

Watercress (Nasturtium Officinale) is a rapidly growing aquatic or semi aquatic perennial plant. It contains health promoting phytochemicals endowed in therapeutic properties.[40] Because chemical agents do not provide efficient microbial reductions, watercress has been tested with gamma irradiation treatment in order to improve both safety and the shelf life of the product.[41] It is traditionally used on horticultural products to prevent sprouting and post-packaging contamination, delay post-harvest ripening, maturation and senescence.[32]

In a Food Chemistry food journal, scientists studied the suitability of gamma irradiation of 1, 2, and 5 kGy for preserving quality parameters of the fresh cut watercress at around 4 degrees Celsius for 7 days. They determined that a 2 kGy dose of irradiation was the dose that contained most similar qualities to non-stored control samples, which is one of the goals of irradiation.[30] 2 kGy preserved high levels of reducing sugars and favoured PUFA; while samples of the 5 kGy dose revealed high contents of sucrose and MUFA. Both cases the watercress samples obtained healthier fatty acids profiles.[31] However, a 5kGy dose better preserved the antioxidant activity and total flavonoids.[32]

Long term impacts[edit]

If the majority of food was irradiated at high-enough levels to significantly decrease its nutritional content, there would be an increased risk to develop illnesses that are nutritionally-based if additional steps, such as changes in eating habits, were not taken to mitigate this.[42] Furthermore, for at least three studies on cats, the consumption of irradiated food was associated with a loss of tissue in the myelin sheath, leading to reversible paralysis. Researchers suspect that reduced levels of vitamin A and high levels of free radicals may be the cause.[43] This effect is thought to be specific to cats and has not been reproduced in any other animal. To produce these effects, the cats were fed solely on food that was irradiated at a dose at least five times higher than the maximum allowable dose.[43]

It may seem reasonable to assume that irradiating food might lead to radiation-tolerant strains, similar to the way that strains of bacteria have developed resistance to antibiotics. Bacteria develop a resistance to antibiotics after an individual uses antibiotics repeatedly. Much like pasteurization plants, products that pass through irradiation plants are processed once, and are not processed and reprocessed. Cycles of heat treatment have been shown to produce heat-tolerant bacteria, yet no problems have appeared so far in pasteurization plants. Furthermore, when the irradiation dose is chosen to target a specific species of microbe, it is calibrated to doses several times the value required to target the species. This ensures that the process randomly destroys all members of a target species.[44] Therefore, the more irradiation-tolerant members of the target species are not given any evolutionary advantage. Without evolutionary advantage, selection does not occur. As to the irradiation process directly producing mutations that lead to more virulent, radiation-resistant strains, the European Commission's Scientific Committee on Food found that there is no evidence; on the contrary, irradiation has been found to cause loss of virulence and infectivity, as mutants are usually less competitive and less adapted.[45]


The argument is made[by whom?] that there is a lack of long-term studies and, therefore, the safety of irradiated food is not scientifically proven,[46] in spite of the fact that hundreds of animal feeding studies of irradiated food, including multigenerational studies, have been performed since 1950.[5] Endpoints investigated have included subchronic and chronic changes in metabolism, histopathology, function of most systems, reproductive effects, growth, teratogenicity, and mutagenicity. A large number of studies have been performed; meta-studies have supported the safety of irradiated food.[5][6][7][8][9]

The below experiments are cited by food irradiation opponents, but either could not be verified in later experiments, could not be clearly attributed to the radiation effect, or could be attributed to an inappropriate design of the experiment.[5][18]

  • India's National Institute of Nutrition (NIN) found an elevated rate of cells with more than one set of genes (polyploidy) in humans and animals when fed wheat that was irradiated recently (within 12 weeks). Upon analysis, scientists determined that the techniques used by the NIN allowed for too much human error and statistical variation; therefore, the results where unreliable. After multiple studies by independent agencies and scientists, no correlation between polyploidy and irradiation of food could be found.[18]

Indirect effects of irradiation[edit]

The indirect effects of irradiation are the concerns and benefits of irradiation that are related to how making food irradiation a common process will change the world, with emphasis on the system of food production.

If irradiation was to become common in the food handling process there would be a reduction of the prevalence of foodborne illness and potentially the eradication of specific pathogens.[47] However, multiple studies suggest that an increased rate of pathogen growth may occur when irradiated food is cross-contaminated with a pathogen, as the competing spoilage organisms are no longer present.[48] This being said, cross contamination itself becomes less prevalent with an increase in usage of irradiated foods.[49]

The ability to remove bacterial contamination through post-processing by irradiation may reduce the fear of mishandling food which could cultivate a cavalier attitude toward hygiene and result in contaminants other than bacteria. However, concerns that the pasteurization of milk would lead to increased contamination of milk were prevalent when mandatory pasteurization was introduced, but these fears never materialized after adoption of this law. Therefore, it is unlikely for irradiation to cause an increase of illness due to nonbacteria-based contamination.[50]


Up to the point where the food is processed by irradiation, the food is processed in the same way as all other food. To treat the food, they are exposed to a radioactive source, for a set period of time to achieve a desired dose. Radiation may be emitted by a radioactive substance, or by X-ray and electron beam accelerators. Special precautions are taken to ensure the food stuffs never come in contact with the radioactive substances and that the personnel and the environment are protected from exposure radiation.[51] Irradiation treatments are typically classified by dose (high, medium, and low), but are sometimes classified by the effects of the treatment[52] (radappertization, radicidation and radurization). Food irradiation is sometimes referred to as "cold pasteurization"[53] or "electronic pasteurization"[54] because ionizing the food does not heat the food to high temperatures during the process, and the effect is similar to heat pasteurization. The term "cold pasteurization" is controversial because the term may be used to disguise the fact the food has been irradiated and pasteurization and irradiation are fundamentally different processes.

Treatment costs vary as a function of dose and facility usage. A pallet or tote is typically exposed for several minutes to hours depending on dose. Low-dose applications such as disinfestation of fruit range between US$0.01/lbs and US$0.08/lbs while higher-dose applications can cost as much as US$0.20/lbs.[55]


Typically, when the food is being irradiated, pallets of food are exposed to a source of radiation for a specific time. Dosimeters are placed on the pallet (at various locations) of food to serve as a check and ensure that the correct dose was achieved.[51] Most irradiated food is processed by gamma irradiation.,[56] however the usage of electron beam and X-ray is becoming more popular as well [1]. With gamma irradiation, special precautions are taken because gamma rays are continuously emitted by the radioactive material. In most designs, to nullify the effects of radiation, the radioisotope is lowered into a water-filled storage pool, which absorbs the radiation but does not become radioactive. This allows pallets of the products to be added and removed from the irradiation chamber and other maintenance to be done.[51] Sometimes movable shields are used to reduce radiation levels in areas of the irradiation chamber instead of submerging the source.[citation needed] For x ray and electron irradiation these precautions are not necessary as the radiation is generated by electricity, the source of the radiation can be switched off.[51]

For x-ray, gamma ray and electron irradiation, shielding is required when the foods are being irradiated. This is done to protect workers and the environment outside of the chamber from radiation exposure. Typically permanent or movable shields are used.[51] In some gamma irradiators the radioactive source is under water at all times, and the hermetically sealed product is lowered into the water. The water acts as the shield in this application.[citation needed] Because of the lower penetration depth of electron irradiation, treatment to entire industrial pallets or totes is not possible.[citation needed]


The radiation absorbed dose is the amount energy absorbed per unit weight of the target material. Dose is used because, when the same substance is given the same dose, similar changes are observed in the target material. The SI unit for dose is grays (Gy or J/kg). Dosimeters are used to measure dose, and are small components that, when exposed to ionizing radiation, change measurable physical attributes to a degree that can be correlated to the dose received. Measuring dose (dosimetry) involves exposing one or more dosimeters along with the target material.[57][58]

For purposes of legislation doses are divided into low (up to 1 kGy), medium (1 kGy to 10 kGy), and high-dose applications (above 10 kGy).[citation needed] High-dose applications are above those currently permitted in the US for commercial food items by the FDA and other regulators around the world.[59] Though these doses are approved for non commercial applications, such as sterilizing frozen meat for NASA astronauts (doses of 44 kGy)[60] and food for hospital patients.

Applications By Overall Average Dose
Application Dose (kGy)
Low dose (up to 1 kGy) Inhibit sprouting[a] 0.03-0.15 kGy
Delay fruit ripening 0.03-0.15 kGy
Stop insect/parasite infestations[b] 0.07-1.00 kGy
Medium dose (1 kGy to 10 kGy) Delay spoilage of meat[c] 1.50–3.00 kGy
Reduce risk of pathogens in meat[c] 3.00–7.00 kGy
Increase sanitation[d] of spices[61] 10.00 kGy
High dose (above 10 kGy) Sterilization[e] of packaged meat[c] 25.00-70.00 kGy
Increase juice yield[citation needed]
Improve re-hydration[citation needed]


Efficiency illustration of the different radiation technologies (electron beam, X-ray, gamma rays)

Electron irradiation uses a stream of electrons accelerated by an electric voltage or radio frequency wave to a velocity close to the speed of light. Electrons have mass and negative electric charge, and therefore electron beams at the energies allowed for food irradiation do not penetrate into the product beyond several centimeters, depending on product density.

Gamma irradiation involves packets of light (photons) that originate from radioactive decay of atomic nuclei. Each element gives rise to Gamma rays with specific energies characteristic of the source element, these rays have zero mass and no electrical charge. The ones used for food irradiation are able to penetrate through food products. The radioactive isotope radioisotope cobalt-60 is used as the source in all commercial scale gamma irradiation facilities.[56] Gamma irradiation is most widely used technology because the deeper penetration of the gamma rays enables administering treatment to entire industrial pallets or totes (reducing the need for material handling) and it is significantly less expensive than using an X-ray source. Generally cobalt-60 is used as a radioactive source for gamma irradiation. Cobalt-60 is bred from cobalt-59 using neutron irradiation in specifically designed nuclear reactors.[56] In limited applications caesium-137, a less costly alternative recovered during the processing of spent nuclear fuel, is used as a radioactive source. Insufficient quantities are available for large scale commercial use. An incident where water-soluble caesium-137 leaked into the source storage pool requiring NRC intervention[62] has led to near elimination of this radioisotope.

Irradiation by X-ray is similar to irradiation by gamma rays but the rays produced have a distribution of energetic packets of light (X-rays). X-rays are generated by colliding accelerated electrons with a dense material (this process is known as bremsstrahlung-conversion), and the x-rays so produced have a spectrum characteristic of the dense target material. Like electron beams, x rays do not necessitate the use of radioactive materials and can be switched off when not needed.[63] X-rays ability to penetrate the target is similar to gamma irradiation. X-ray machines produce better dose uniformity than Gamma irradiation but require much more electricity as only as much as 12% of the input energy is converted into X-rays.[56]


The cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions, i.e., packaging and stacking requirements, construction costs, financing arrangements, and other variables particular to the situation.[64] Irradiation is a capital-intensive technology requiring a substantial initial investment, ranging from $1 million to $5 million. In the case of large research or contract irradiation facilities, major capital costs include a radiation source, hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), land (1 to 1.5 acres), radiation shield, and warehouse. Operating costs include salaries (for fixed and variable labor), utilities, maintenance, taxes/insurance, cobalt-60 replenishment, general utilities, and miscellaneous operating costs.[55][65]

Standards & regulations[edit]

The Codex Alimentarius represents the global standard for irradiation of food, in particular under the WTO-agreement. Member states are free to convert those standards into national regulations at their discretion,[citation needed] therefore regulations about irradiation differ from country to country.

The United Nations Food and Agricultural Organization (FAO) has passed a motion to commit member states to implement irradiation technology for their national phytosanitary programs; the General assembly of the International Atomic Energy Agency (IAEA) has urged wider use of the irradiation technology.[citation needed]


The Radura symbol, as required by U.S. Food and Drug Administration regulations to show a food has been treated with ionizing radiation.

The provisions of the Codex Alimentarius are that any "first generation" product must be labeled "irradiated" as any product derived directly from an irradiated raw material; for ingredients the provision is that even the last molecule of an irradiated ingredient must be listed with the ingredients even in cases where the unirradiated ingredient does not appear on the label. The RADURA-logo is optional; several countries use a graphical version that differs from the Codex-version. The suggested rules for labeling is published at CODEX-STAN – 1 (2005),[66] and includes the usage of the Radura symbol for all products that contain irradiated foods. The Radura symbol is not a designator of quality. The amount of pathogens remaining is based upon dose and the original content and the dose applied can vary on a product by product basis.

The European Union follows the Codex's provision to label irradiated ingredients down to the last molecule of irradiated food. The European Community does not provide for the use of the Radura logo and relies exclusively on labeling by the appropriate phrases in the respective languages of the Member States. The European Union enforces its irradiation labeling laws by requiring its member countries to perform tests on a cross section of food items in the market-place and to report to the European Commission. The results are published annually in the OJ of the European Communities.[67]

The US defines irradiated foods as foods in which the irradiation causes a material change in the food, or a material change in the consequences that may result from the use of the food. Therefore, food that is processed as an ingredient by a restaurant or food processor is exempt from the labeling requirement in the US. This definition is not consistent with the Codex Alimentarius. All irradiated foods must bear a slightly modified[66] Radura symbol at the point of sale and use the term "irradiated" or a derivative there of, in conjunction with explicit language describing the change in the food or its conditions of use.[68]

Food safety[edit]

In 2003, the Codex Alimentarius removed any upper dose limit for food irradiation as well as clearances for specific foods, declaring that all are safe to irradiate. Countries such as Pakistan and Brazil have adopted the Codex without any reservation or restriction. Other countries, including New Zealand, Australia, Thailand, India, and Mexico, have permitted the irradiation of fresh fruits for fruit fly quarantine purposes, amongst others.[citation needed]

Standards that describe calibration and operation for radiation dosimetry, as well as procedures to relate the measured dose to the effects achieved and to report and document such results, are maintained by the American Society for Testing and Materials (ASTM international) and are also available as ISO/ASTM standards.[69]

All of the rules involved in processing food are applied to all foods before they are irradiated.

United States[edit]

In the United States, each new food is approved separately with a guideline specifying a maximum dosage; in case of quarantine applications the minimum dose is regulated. Packaging materials containing the food processed by irradiation must also undergo approval. Food irradiation in the United States is primarily regulated by the FDA[70] since it is considered a food additive. The United States Department of Agriculture (USDA) amends these rules for use with meat, poultry, and fresh fruit.[71]

The United States Department of Agriculture (USDA) has approved the use of low-level irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to a number of insect pests, including fruit flies and seed weevils. Under bilateral agreements that allows less-developed countries to earn income through food exports agreements are made to allow them to irradiate fruits and vegetables at low doses to kill insects, so that the food can avoid quarantine.

The U.S. Food and Drug Administration (FDA) and the USDA have approved irradiation of the following foods and purposes:

  • Packaged refrigerated or frozen red meat[72] — to control pathogens (E. Coli O157:H7 and Salmonella), and to extend shelf life.[73]
  • Packaged poultry — control pathogens (Salmonella and Camplylobacter).[73]
  • Fresh fruits, vegetables and grains — to control insects and inhibit growth, ripening and sprouting.[73]
  • Pork — to control trichinosis.[73]
  • Herbs, spices and vegetable seasonings[74] — to control insects and microorganisms.[73]
  • Dry or dehydrated enzyme preparations — to control insects and microorganisms.[73]
  • White potatoes — to inhibit sprout development.[73]
  • Wheat and wheat flour — to control insects.[73]
  • Loose or bagged fresh iceberg lettuce and spinach[75]

European Union[edit]

European law dictates that all member countries must allow the sale of irradiated dried aromatic herbs, spices and vegetable seasonings.[76] However, these Directives allow Member States to maintain previous clearances food categories the EC's Scientific Committee on Food (SCF) had previously approved (the approval body is now the European Food Safety Authority). Presently, Belgium, Czech Republic, France, Italy, Netherlands, Poland, and the United Kingdom allow the sale of many different types of irradiated foods.[77] Before individual items in an approved class can be added to the approved list, studies into the toxicology of each of such food and for each of the proposed dose ranges are requested. It also states that irradiation shall not be used "as a substitute for hygiene or health practices or good manufacturing or agricultural practice". These Directives only control food irradiation for food retail and their conditions and controls are not applicable to the irradiation of food for patients requiring sterile diets.

Because of the Single Market of the EC any food, even if irradiated, must be allowed to be marketed in any other Member State even if a general ban of food irradiation prevails, under the condition that the food has been irradiated legally in the state of origin. Furthermore, imports into the EC are possible from third countries if the irradiation facility had been inspected and approved by the EC and the treatment is legal within the EC or some Member state.[78][79][80][81][82]


Australia banned irradiated cat food after a national scare where cats suffered from paralyzation after eating a specific brand of highly irradiated catfood for an extended period of time. The suspected culprit was malnutrition from consuming food depleted of Vitamin A by the irradiation process.[83][84] The incident was linked only to a single batch of one brand's product and no illness was linked to any of that brand's other irradiated batches of the same product or to any other brand of irradiated cat food. This, along with incomplete evidence indicating that the cat food was not sufficiently depleted of Vitamin A[85] makes irradiation a less likely cause.[86] Further research has been able to experimentally induce the paralyzation of cats by via Vitamin A deficiency by feeding highly irradiated food.[43] For more details see the cumulative impacts of irradiation section.

Nuclear safety & security[edit]

Interlocks and safeguards are mandated to minimize this risk. There have been radiation related accidents, deaths, and injury at such facilities, many of them caused by operators overriding the safety related interlocks.[87] In a radiation processing facility, radiation specific concerns are supervised by special authorities, while "Ordinary" occupational safety regulations are handled much like other businesses.

The safety of irradiation facilities is regulated by the United Nations International Atomic Energy Agency and monitored by the different national Nuclear Regulatory Commissions. The regulators enforce a safety culture that mandates that all incidents that occur are documented and thoroughly analyzed to determine the cause and improvement potential. Such incidents are studied by personnel at multiple facilities, and improvements are mandated to retrofit existing facilities and future design.

In the US the Nuclear Regulatory Commission (NRC) regulates the safety of the processing facility, and the United States Department of Transportation (DOT) regulates the safe transport of the radioactive sources.

Irradiated food supply[edit]

Authorities in some countries use tests that can detect the irradiation of food items to enforce labeling standards and to bolster consumer confidence.[88][89][90] The European Union monitors the market to determine the quantity of irradiated foods, if irradiated foods are labeled as irradiated, and if the irradiation is performed at approved facilities.

Irradiation of fruits and vegetables to prevent the spread of pest and diseases across borders has been increasing globally. In 2010, 18446 tonnes of fruits and vegetables were irradiated in six countries for export quarantine control; the countries follow: Mexico (56.2%), United States (31.2%), Thailand (5.18%), Vietnam (4.63%), Australia (2.69%), and India (0.05%). The three types of fruits irradiated the most were guava (49.7%), sweet potato(29.3%) and sweet lime (3.27%).[91]

In total, 103 000 tonnes of food products were irradiated on mainland United States in 2010. The three types of foods irradiated the most were spices (77.7%), fruits and vegetables (14.6%) and meat and poultry (7.77%). 17 953 tonnes of irradiated fruits and vegetables were exported to the mainland United States.[91] Mexico, the United States' state of Hawaii, Thailand, Vietnam and India export irradiated produce to the mainland U.S.[91][92][93] Mexico, followed by the United States' state of Hawaii, is the largest exporter of irradiated produce to the mainland U.S.[91]

In total, 6 876 tonnes of food products were irradiated in European Union countries in 2013; mainly in four member state countries: Belgium (49.4%), the Netherlands (24.4%), Spain (12.7%) and France (10.0%). The two types of foods irradiated the most were frog legs (46%), and dried herbs and spices (25%). There has been a decrease of 14% in the total quantity of products irradiated in the EU compared to the previous year 2012 (7 972 tonnes) [94]

Timeline of the history of food irradiation[edit]

  • 1895 Wilhelm Conrad Röntgen discovers X-rays ("bremsstrahlung", from German for radiation produced by deceleration)
  • 1896 Antoine Henri Becquerel discovers natural radioactivity; Minck proposes the therapeutic use[95]
  • 1904 Samuel Prescott describes the bactericide effects Massachusetts Institute of Technology (MIT)[96]
  • 1906 Appleby & Banks: UK patent to use radioactive isotopes to irradiate particulate food in a flowing bed[97]
  • 1918 Gillett: U.S. Patent to use X-rays for the preservation of food[98]
  • 1921 Schwartz describes the elimination of Trichinella from food[99]
  • 1930 Wuest: French patent on food irradiation[100]
  • 1943 MIT becomes active in the field of food preservation for the U.S. Army[101]
  • 1951 U.S. Atomic Energy Commission begins to co-ordinate national research activities
  • 1958 World first commercial food irradiation (spices) at Stuttgart, Germany[102]
  • 1970 Establishment of the International Food Irradiation Project (IFIP), headquarters at the Federal Research Centre for Food Preservation, Karlsruhe, Germany
  • 1980 FAO/IAEA/WHO Joint Expert Committee on Food Irradiation recommends the clearance generally up to 10 kGy "overall average dose"[6]
  • 1981/1983 End of IFIP after reaching its goals
  • 1983 Codex Alimentarius General Standard for Irradiated Foods: any food at a maximum "overall average dose" of 10 kGy
  • 1984 International Consultative Group on Food Irradiation (ICGFI) becomes the successor of IFIP
  • 1998 The European Union's Scientific Committee on Food (SCF) voted "positive" on eight categories of irradiation applications[103]
  • 1997 FAO/IAEA/WHO Joint Study Group on High-Dose Irradiation recommends to lift any upper dose limit[7]
  • 1999 The European Union issues Directives 1999/2/EC (framework Directive) and 1999/3/EC (implementing Directive) limiting irradiation a positive list whose sole content is one of the eight categories approved by the SFC, but allowing the individual states to give clearances for any food previously approved by the SFC.
  • 2000 Germany leads a veto on a measure to provide a final draft for the positive list.
  • 2003 Codex Alimentarius General Standard for Irradiated Foods: no longer any upper dose limit
  • 2003 The SCF adopts a "revised opinion" that recommends against the cancellation of the upper dose limit.[45]
  • 2004 ICGFI ends
  • 2011 The successor to the SFC, European Food Safety Authority (EFSA), reexamines the SFC's list and makes further recommendations for inclusion.[104]

See also[edit]


  1. ^ bulbs and tubers
  2. ^ to help clear quarantine
  3. ^ a b c fresh or frozen red meat, poultry, and seafood
  4. ^ improve hygienic quality
  5. ^ shelf stable without refrigeration


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Further reading[edit]

External links[edit]