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Food Irradiation

What is food irradiation?

Food irradiation is a procedure which reduces or rids food of unwanted pests and micro-organisms (called phytosanitary procedures) that cause foodborne illness or present a biosecurity risk. When food is irradiated it passes through an enclosed chamber where it is exposed to an approved dose of ionising energy. This penetrates the food and destroys harmful organisms without altering the food itself. Food is exposed to an appropriate dose of one of three energy types.

Under the standard covering the irradiation of food in Australia and New Zealand, irradiation energy can be in the form of Cobalt 60 sourced gamma rays, machine generated x-rays or an electrically generated electron beam.

Cobalt 60 is a radioactive source of energy. This substance gives off high energy photons, called gamma rays, which can penetrate foods to a depth of several feet. Cobalt 60 does not emit neutrons, which means it does not make anything around it radioactive.

Electron beams and x-ray technologies are energy sources that can be switched on and off and do not have radioactive properties.

Why is food irradiated?

The presence of harmful micro-organisms in food is a problem for public health authorities worldwide and pests are a threat to New Zealand’s biosecurity. Irradiation of food is similar to the pasteurisation of milk with the same aim of making it safer for consumers. Irradiation can be an effective way of reducing foodborne hazards and ensuring that harmful organisms are not in the food we buy.

For example, irradiation destroys the micro-organisms that cause food decomposition and foodborne illnesses. It can also get rid of unwanted pests that can accompany food when it is traded regionally or imported from other countries.

What irradiated foods are approved for sale in New Zealand?

Biosecurity New Zealand has approved the importation of irradiated tropical fruit from Queensland, Australia. Food Standards Australia New Zealand (FSANZ) has approved and given food safety clearance to the use of irradiation as a phytosanitary treatment for the following imported fruits:

Mango	Rambutan
Longan	Lychee
Papaya	Custard apple
Breadfruit	Carambola

Along with these fruits the only other products available in New Zealand, and permitted to be irradiated in prescribed doses set out in the Foods Standards Code, are herbs and spices and herbal infusions, excluding tea.

Foods are not allowed to be irradiated unless they have been through a pre-market safety assessment process conducted by FSANZ. The Food Standards Code has been formally changed to reflect the outcome of this assessment.

Before these foods are imported into New Zealand, an Import Health Standard that deals with quarantine concerns for these foods is required from the Ministry of Agriculture and Forestry (MAF).

Does irradiation change food?

At the approved doses, changes to the nutritional value of the food caused by irradiation are insignificant and do not pose any public health and safety concerns. The high energy ray is absorbed as it passes through food, and gives up its energy. The food is slightly warmed. Some treated foods may taste slightly different, just as pasteurized milk tastes slightly different from unpasteurized milk. There are no other significant changes to these foods.

Does irradiation make food radioactive?

No. The only radioactive source of energy used in irradiation is Cobalt 60 which emits gamma rays that penetrate the food and rid it of any undesirable micro-organisms that maybe harmful to human health as well as pests that could harm the environment. The Cobalt 60 does not emit neutrons however and this means that it lacks the ability to transfer radioactivity to objects around it such as the food it is treating. Electron beams and X-rays are not radioactive sources of energy. The process cannot cause the food to become radioactive no matter how long the food is exposed to the radiation or how large the dose of radiation absorbed.

Is it safe to eat irradiated food?

Yes. Irradiation of food does not make the food unsafe to eat. More than 40 countries including France, Australia and the United States have approved the use of irradiation as a food safety procedure. The World Health Organisation, the Food and Drug Administration in the US and the American Medical Association all agree that irradiated food products are safe to eat.

The safety of irradiating tropical fruits has also been examined by FSANZ and available studies on irradiated fruits show that there are no safety concerns. Irradiation of tropical fruits to a maximum of 1KGy (kiloGrey) employing good manufacturing / irradiation practices is considered safe.

How do I know if food has been irradiated?

Under the Australia New Zealand Food Standards Code, which the New Zealand Food Safety Authority is responsible for enforcing in New Zealand, foods that have been irradiated must be clearly labelled showing that they have undergone this treatment.

For items such as fruit that do not carry labels, a statement must be displayed beside the produce stating that it has been treated with ionising radiation. This ensures that consumers can choose if they want to eat irradiated foods.