Consumer Questions About Food Irradiation

Q:  Does the irradiation process make food radioactive?
A:  No. Irradiation under controlled conditions does not make food radioactive.

Everything in our environment, including food, contains trace amounts of radioactivity. This means that this trace amount (about 150 to 200 becquerels) of natural radioactivity (from elements such as potassium) is unavoidably in our daily diets.

The irradiation process involves passing the food through a radiation field at a set speed to control the amount of energy, or dose absorbed, by the food. The food itself never comes into direct contact with the radiation source.

Q:  What is the difference between the terms "irradiated food" and "radioactive food?"
A:  Irradiated foods are those that have been deliberately processed with certain types of radiation energy to bring about some desirable properties (for example, to inhibit sprouting or to destroy food poisoning bacteria).

Many other materials are commercially irradiated during manufacturing, such as cosmetics, wine bottle corks, hospital supplies and medical products, and some types of food packaging.

Q: How will I know if the food I'm buying has been irradiated?
A:  Since 1986, all irradiated products must carry the international symbol called a radura, which resembles a stylized flower. FDA requires that both the logo and statement appear on packaged foods, bulk containers of unpackaged foods, on placards at the point of purchase (for fresh produce), and on invoices for irradiated ingredients and products sold to food processors.

Processors may add information explaining why irradiation is used; for example, "treated with irradiation to inhibit spoilage" or "treated with irradiation instead of chemicals to control insect infestation."

Accurate plant records are essential to regulation because there is no way to verify or detect if a product has been irradiated, or how much radiation it has received.

Q:  Are chemical changes in irradiated food, such as the formation of radiolytic products, harmful?
A:  No. In general, the irradiation process produces very little chemical change in food. None of the changes known to occur have been found to be harmful or dangerous.

Some of the changes produce "radiolytic" products. These are familiar products, such as glucose, formic acid, acetaldehyde, and carbon dioxide, that are naturally present in foods or are formed by heat processing. Their safety has been examined very critically and no evidence of harm has been found.

Q:  Do the "free radicals" which are produced during irradiation affect the safety of the food?
A:   No. There is no evidence to suggest that free radicals affect the safety of irradiated food.

See the glossary for more information.

Q:  Does irradiation adversely affect the nutritional value of food?
A:   No more so than other food processing and preservation methods used to achieve the same purpose. Extensive research has shown that macronutrients, such as protein, carbohydrates, and fat, are relatively stable to radiation doses of up to 10 kilogray.

Q:  Are foods already contaminated with a microbial toxin or virus suitable for irradiation?
A:  No. Only foods of good hygienic quality should be irradiated. In this respect, irradiation does not differ from heat pasteurization, freezing, or other food processes. While these processes can destroy bacteria, they may not totally destroy preformed toxins and viruses already in the food.

Q:  Can irradiation make spoiled food good, or clean up "dirty" food?
A:  No. Neither irradiation nor any other food treatment can reverse the spoilage process and make bad food good. If food already looks, tastes or smells bad--signs of spoilage--it cannot be "saved" by any treatment, including irradiation

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Q:  Does irradiation food that contains pesticide residues or additives present any health hazards?
A:  No. There is no scientific evidence to indicate any health hazard associated with irradiation of food containing pesticide residues and additives.


Q:  Are irradiated materials used to package foods?
A:  Yes. Laminated plastic films with aluminum foil are routinely sterilized by radiation. They are used for hermetically sealed "bag-in-a-box" products, such as tomato paste, fruit juices, and wines.


Q:  Do workers at irradiation facilities face dangers from long-term or accidental exposure to radiation?
A:  Any industrial activity includes certain risks to human beings and the environment. One of the risks at irradiation facilities is associated with the potential hazard of accidental exposure to ionizing radiation.

Under normal operating conditions, all exposures of workers to radiation are prevented because the radiation source is shielded. Irradiators are designed with several levels of protection to detect equipment malfunction and to protect personnel from accidental radiation exposure.

Q:  More radioactive materials will need to be transported if more food irradiators are built. What steps have been taken to minimize the danger of radioactive spills from transport accidents?
A:  Radioactive material required for irradiators is transported in lead-shielded steel casks. These are designed to meet national and international standards modeled on the Regulations for Safe Transport of Radioactive Materials of the International Atomic Energy Agency.

Q:  Can an accident at a gamma irradiation facility lead to "meltdown" of the irradiator and release of radioactivity that would contaminate the environment and endanger people living nearby?
A:  No. It is impossible for a "meltdown" to occur in a gamma irradiator or for the radiation source to explode. The source of radiation energy used at irradiators cannot produce neutrons--substances which can make materials radioactive--so no such "chain reaction" can occur.


Q:  What precautions are taken to ensure that foods are properly treated with irradiation?
A:  Irradiation facilities must be approved by governmental authorities before construction. In addition, they are subject to regular inspections, audits, and other reviews to ensure they are safely and properly operated.


Q:  Are there tests to detect whether food has been irradiated?
A:  Yes, to some extent. Some scientific tests are being studied for use in determining whether foods have been irradiated. These include thermoluminescence measurement for detection of irradiated spices and electron spin resonance spectroscopy for determining irradiation of meats, poultry, and seafood containing any bone or shells, and some specific chemical tests.

Q: 
Will irradiation increase the cost of food?
A:  Any food process will add cost. In most cases, however, food prices would not necessarily rise just because a product has been treated. Many variables affect food prices, and one of them is the cost of processing.

Canning, freezing, pasteurization, refrigeration, fumigation, and irradiation will add cost to the product. These treatments will also bring benefits to consumers in terms of availability and quantity, storage life, convenience, and improved hygiene of the food.

Q:  How much does a typical food irradiation facility cost?
A:  The cost to build a food irradiation plant is in the range of $1 million to $3 million, depending on size, processing capacity, and other factors. This is within the range of plant costs for other food technologies.

Q:  What irradiated food products have been commercially marketed on a trial basis?
A:  Many irradiated food products have been sold in a number of marketing trials, including apples, potatoes, onions, strawberries, mangoes, papaya, dried fish, and fermented pork sausages.

  • Article History
    • Revision Date: 6/9/2010

Food Safety Tip of the Day

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Use a plate, pan or even a plastic bag defrosting raw meats, poultry, or seafood in a refrigerator. Containing the juices that form during the defrosting process helps to prevent potential cross contamination of other items in the refrigerator. These juices may contain illness-causing bacteria that may contaminate ready-to-eat foods unless otherwise contained.

Source: Partnership for Food Safety Education

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