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Food and Nutrition

Frequently Asked Questions Regarding Food Irradiation

Food irradiation was first developed in the United States and the United Kingdom during the 1960s. Despite being one of the most studied food technologies, information on food irradiation has not been well communicated to the broader public, largely because of the complexity of the subject matter. The purpose of these questions and answers is to provide some basic facts about this process.

1. What is food irradiation?

Food irradiation is a method of preserving food by using a type of radiation energy. It is one of several techniques that can be used by food producers to protect the quality of food before it reaches the grocery store. Other techniques include cooking or heating, canning, chemical treatments, and steam pasteurization. Food irradiation could also be used in combination with these techniques.

2. Why irradiate food and how does irradiation protect food?

Irradiation is used in food processing for several reasons:

  • To prevent food poisoning: by reducing the level of harmful bacteria such as E.coli O157:H7, Salmonella and Campylobacter, and parasites which cause food borne diseases.
  • To prevent spoilage: by reducing the microbial load on foods, meaning it destroys bacteria, molds and yeast which cause food to spoil, and controls insect and parasite infestation.
  • To increase shelf life: by slowing the ripening or sprouting in fresh fruits and vegetables, thereby allowing for longer shelf life.

3. How much radiation is used?

The amount of radiation energy used or needed for a particular application varies depending on the food and the reason for irradiating. Typically, to increase shelf life or to prevent spoilage a low dose of irradiation is required, only 1 kilogray (kGy) of absorbed energy. To prevent food poisoning, the dose will depend on the type of bacteria being targeted and the type of food. An absorbed dose of up to 3 kGy is usually sufficient to kill Salmonella in fresh chicken. Generally, it takes higher levels of radiation to kill parasites and insects. Viruses, for the most part, are not destroyed by the irradiation levels that are suitable for use in foods.

4. Is irradiated food radioactive?

No, irradiated foods do not become radioactive. During irradiation the food never comes into contact with the radioactive source. In addition, the Food and Drug Regulations places upper limits on the energy levels that may be used for treatment of foods. No radioactive energy (waves) remain in the food after treatment.

5. Are there currently any irradiated foods on the market in Canada?

To date, the following products have been examined by Health Canada and have been approved for irradiation: potatoes, onions, wheat, flour, whole wheat flour, whole and ground spices, and dehydrated seasoning preparations. Currently, the technology is not used widely on food commodities in Canada. So far, the main use of irradiation in Canada has been on spices.

6. Is the irradiation of these foods mandatory?

No. Regulations allow the irradiation of these foods at the discretion of food producers. It is not mandatory.

7. Can the irradiation of food cause harm to the consumer?

International bodies, such as the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), recognize the irradiation process as one safe way of reducing levels of organisms that cause food borne illness and disease in food products. The use of food irradiation reduces the levels of these disease organisms in food purchased by the consumer, and the irradiated food remains nutritious and safe for consumption .

8. How is food irradiated?

During the irradiation process, food is exposed to an ionizing energy source. Three different energy sources may be used: gamma rays, electron beams and x-rays. The length of time the food is exposed to the source and the energy level determine the dose of irradiation. The doses used for food irradiation do not result in the food becoming radioactive.

9. What changes to food are caused by irradiation?

Irradiation causes minor chemical modifications, similar to cooking, and some irradiated foods may taste slightly different. Food irradiation does not lead to change in the food that, from a toxicological point of view, would have an adverse effect on human health. Food irradiation, at permitted levels, does not diminish the nutritional value of the food. Any living cells in the food, including potentially harmful bacteria, are killed or damaged.

10. Does treatment by irradiation guarantee food safety?

No. Nothing can guarantee food safety, but food irradiation greatly reduces bacteria and other microorganisms that may be present in food. Irradiated food must still be handled, stored, and cooked properly like all other foods. The rules of safe food handling - proper sanitation, packaging, storage and preparation - still need be followed.

Irradiation cannot be used to restore food that is already spoiled. If food looks, smells or tastes bad before irradiation, it will still look, smell and taste bad after irradiation.

11. Who sets standards for the appropriate level of radiation?

Canada sets its own standards for irradiated foods, as do many other countries. Canadian standards are in the Food and Drug Regulations and consist of a list of foods which may be irradiated, the maximum doses allowed and any other appropriate requirements. Health Canada is responsible for establishing these regulations and standards.

The Food and Drug Regulations apply to foods offered for sale in Canada, no matter where they were produced or, in this case, where they were irradiated. It is the responsibility of the Canadian Food Inspection Agency (CFIA) to enforce the regulations.

12. Can I tell if a food has been irradiated?

All irradiated foods must be labelled. In addition to a written description, such as "irradiated", a distinctive logo, the "Radura", must be on the package to identify the product as irradiated. Most consumers cannot detect any difference in the appearance, odour or taste of the food.

13. Who is responsible for the regulation of irradiation in Canada?

In Canada, several federal agencies are involved in regulating aspects of the food irradiation process:

The Health Products and Food Branch of Health Canada, through the Food and Drugs Act, is responsible for establishing standards related to the safety of foods sold to the Canadian consumer. It evaluates the safety of foods and the effectiveness of food irradiation, and assesses the chemical, microbiological and nutritional changes that occur in foods during the irradiation process before approving any new use of irradiation to ensure the safety and nutritional quality of the food.

The Canadian Food Inspection Agency (CFIA) is responsible for all enforcement and compliance issues relating to irradiated foods. It administers the regulations relating to the labelling of irradiated products under the Food and Drugs Act and the Consumer Packaging and Labelling Act.

The Radiation Protection Bureau (RPB) of Health Canada, is responsible for investigating, communicating and reducing health risks to Canadians from exposure to ionizing and non-ionizing radiation. In particular, they operate a centralized dose record system which contains the occupational radiation dose records of all monitored radiation workers in Canada. They also offer (national) dosimetry services (NDS) for measuring personal and occupational exposure. This information is used by RPB to control occupational exposure to ionizing radiation in the workplace and evaluate dose trends and statistics.

The Canadian Nuclear Safety Commission (CNSC) (formely the Atomic Energy Control Board or AECB) regulates the use of nuclear energy and materials in accordance with Canada's international commitments on the peaceful use of nuclear energy. Food irradiation facilities must comply with these regulations. The CNSC functions as a tribunal, making independent decisions on the licensing of nuclear- related activities in Canada; establishes regulations and sets regulatory policy direction on matters relating to health, safety, security and environment.

14. Is Canada's control of irradiation as strict as in other countries?

Many countries, for example, the US, members of the European community and Australia, regulate food irradiation in much the same way as Canada. In the US, at present, irradiation of red meats, poultry and fresh fruits and vegetables is permitted.

15. Do other countries have lists of foods that have been approved for irradiation?

Health and safety authorities in at least 39 countries have approved irradiation of a combined total of 40 different foods ranging from spices to grain to boneless chicken to fruits and vegetables. The process is being used for commercial purposes in many of those countries. Mexico and the U.S., for example, permit irradiation of a wider range of foods than Canada, while the European Union, to date, has only authorized the irradiation within the whole EU of "dried aromatic herbs, spices and vegetable seasonings." Member states within the EU, however, have clearances of their own, with France being the most permissive and the Netherlands also authorizing a number of foods for irradiation, including dried fruits, pulses, dehydrated vegetables, flakes from cereals, herbs, spices, shrimps, poultry, frog legs, gum arabic, food additives, flavourings and egg products. The US allows the low-dose irradiation of all foods for arthropod disinfection and fresh foods generally to inhibit growth and maturation and also allows the irradiation of dry enzyme preparations, dry spices/seasonings, poultry, frozen meats, refrigerated meat, frozen meat, fresh shell eggs and seeds for sprouting.

16. Is food the only commodity irradiated?

No. Irradiation has been used as a sterilization technique for years on medical disposables and hospital supplies, food packaging materials, cosmetics ingredients and joint implants.

17. Are consumers ready to buy irradiated foods?

Recent experience in the U.S. shows that many consumers are willing to buy irradiated foods. This is particularly true if the purpose of the irradiation is clearly indicated. Consumers are interested in a process that eliminates harmful microbes from the food and reduces the risk of food borne disease. In test marketing of specific irradiated foods, consumers have shown that they are willing to buy them. Typically at least half will buy the irradiated food, if given a choice between irradiated product and the same product non-irradiated. If consumers are first educated about what irradiation is and why it is done, approximately 80% will buy the product in these marketing tests.