Food Irradiation Fact Sheet

What is food irradiation?
Food irradiation is a non-chemical process that treats certain types of food with radiation energy. The radiation is produced either by a cobalt 60 source which emits gamma rays or by electron beams from machines which produce high energy electrons or Xrays.

Food irradiation can be used for the purposes of:

  • food safety – making the food safer for consumers by reducing microbiological risk
  • food preservation – increasing the shelf life of a product by destroying or inactivating enzymes, insects, moulds and yeast that spoils food
  • biosecurity – preventing the entry of viable insect pests into our environment

Food irradiation is another way of preserving food to keep it safe and wholesome, similar to pasteurisation and freezing.

What is New Zealand's existing policy on food irradiation?
Under the Australia New Zealand Food Standards Code (the Code) there are a small number of foods that can be irradiated. The Code currently permits the irradiation of herbs, spices, herbal infusions, selected tropical fruits, persimmons, tomatoes and capsicums. The Code permissions are subject to dosage requirements expressed in Gray (Gy) units.

Where foods have been irradiated the Code requires these foods to carry a label so consumers can choose if they want to eat irradiated foods. For items such as fruit that do not carry labels, a statement must be displayed beside the food to say it has been treated with ionising radiation.

Under our food laws, irradiation can be used to treat specific foods only after Food Standards Australia New Zealand (FSANZ) has conducted a safety assessment. FSANZ only approves irradiation where it concludes this treatment would be safe and would not impact nutrient levels any more than other pest control and food safety treatments.

Are irradiated foods safe and wholesome?
The overwhelming consensus of the scientific community is that irradiation produces safe and nutritious food when carried out in accordance with specified standards.

Over 50 years of research shows that even foods exposed to high doses of irradiation are safe, wholesome and nutritionally adequate. The safety and nutritional adequacy of irradiated foods has been more intensively studied than any other food processing method. Research indicates it is as safe as any other conventional processes such as canning, freezing and pasteurisation, provided that good manufacturing procedures are followed.

Three international agencies: the World Health Organization and the Food and Agricultural Organization of the United Nations, and the International Atomic Energy Agency accept the safety and usefulness of food irradiation. The process is also endorsed by the American Medical Association, the Scientific Committee of the European Union, and the American Spice Trade Association among others.

Overseas, at least 40 countries have been granted clearances or authorisations to irradiate specific foods. The way regulations are administered result in differences in these countries as to whether final authorisations and specific regulations have been put in place. Countries that irradiate food commercially in small volumes include Belgium, China, France, the Netherlands, South Africa and the United States. Another 10-15 countries occasionally irradiate small food batches for research and market testing purposes.

Food irradiation - how does it work?
Food is irradiated by exposing it to a source of ionising radiation. The ionising radiation usually is in the form of gamma rays from a source of cobalt 60, or from a non-radioactive source (electron beam and Xrays) generated from electricity.

Electron beam technology does not require the use of radioactive source material, and can be "turned on and off".

As the gamma rays pass through the food the radiation damages the genetic material of the contaminating organisms so that they can no longer survive or multiply. Like pasteurisation, it can make the food safer to eat by destroying bacteria.

Unlike pasteurisation, it can be used on solids as well as liquids.

Different doses of ionising radiation have different effects. At low doses, irradiation lengthens the shelf-life of certain foods such as strawberries and prevents sprouting of potatoes. At higher doses, irradiation helps reduce amounts of harmful bacteria on foods such as dried herbs and spices and chicken.

Does irradiation cause the food to become radioactive?
The food does not become radioactive for two reasons. Firstly, the gamma rays from cobalt-60 used in food irradiation are not energetic enough to make foods radioactive. Secondly, as the food never comes into direct contact with the source, it is not possible for the food to become contaminated with the radioactive material.

What are its limitations?
Just as you cannot successfully freeze or can all types of food not all types of food can be treated with ionising radiation. For example, many dairy products treated with ionising radiation develop noticeable changes in flavour, odour and colour, even at low doses. This is mainly due to changes in fats similar to when food is exposed to sunlight.

Irradiation is ineffective against viruses.

Food irradiation is not a substitute for proper food handling and cannot enhance food that is deteriorated, contaminated or of inferior quality, or prevent contamination from improper handling after irradiation. Irradiation is an option as part of a total system to improve food hygiene throughout the food processing and handling chain. Food that has spoiled will remain spoiled after irradiation.

Why is food irradiation important to our export/import markets?
New Zealand and many of its export markets guard against the importation of exotic insect pests by requiring a post-harvest disinfestation treatment of commodities that can carry pests (e.g. some fresh fruits, vegetables, nuts, cereals and grains).

Without the ability to permit the sale of irradiated foods, New Zealand would be dependent on chemical alternatives to safeguard certain foods while other countries are phasing out or banning the use of these chemicals.

New Zealand does not export irradiated fresh produce, as no food irradiation facilities are approved in New Zealand. Imported fresh produce must comply with the requirements of any relevant import health standard. Irradiation can be used as a biosecurity treatment for imported fresh produce (e.g. fruit fly) but only where this has been specifically permitted in an import health standard.

MPI is responsible for the development of import health standards. Currently there are import health standards for irradiated mangoes, lychees and papaya from Australia and irradiated mangoes from Vietnam. An import health standard for capsicums and tomatoes from Australia is under consideration.

Can irradiated foods be distinguished from other foods?
Irradiation produces small changes in food, but generally the constituents of irradiated foods are not unique and cannot be distinguished from those in other foods, either non-irradiated or processed by other methods. However, tests are now available to detect irradiated foods in most situations. It may not always be possible to detect an irradiated ingredient when it is a minor food component of a larger food product or if, for example, an irradiated spice is blended with a large volume of non-irradiated spice.

The consumer would not be able to detect that a food has been irradiated.

How will I know what foods have been treated with irradiation?
All irradiated foods must be labelled so that consumers can make an informed choice.

Does irradiation affect New Zealand’s nuclear free stance?
Radiation technology is used in medical diagnoses and treatment through the use of x-rays, and nuclear medicine. It is commonly used in the treatment of cancer. Radiation technology is also used in a variety of detection and measurement instruments in industry (including the food and bottling industries). None of these uses affects New Zealand's nuclear-free stance - nor does irradiation of food./p>

The Code prohibits the irradiation of food, or ingredients or components of food, unless specific permission is given. As New Zealand retailers will be able to import and sell foods irradiated overseas as specified under the Code, there may be no increase in the number of radiation facilities in this country. Currently there are no food radiation facilities approved in New Zealand. If local food processors decided to apply the technology here, then, depending on the particular use, they may be able to choose a non-radioactive (electron beam) source of irradiation.

Any consideration of the building of a food irradiation plant would be subject to other legislation including the Resource Management Act 1991 and the Radiation Protection Act 1965.

Other sources of information:

Labelling requirements for irradiated foods - information for food businesses

The Royal Society of New Zealand, PO Box 598, Wellington.

Food Standards Australia New Zealand, PO Box 10 559, The Terrace, Wellington

Ministry of Health, PO Box 5013, Wellington

GNSScience PO Box 30-368 , Lower Hutt

National Radiation Laboratory, Environmental Science & Research Ltd, PO Box 29-181, Christchurch

Facts about food irradiation A series of Fact Sheets from the International Consultative Group on Food Irradiation



Last Updated: 10 July 2013

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