Irradiation can be used to kill bacteria that cause food poisoning, such as salmonella, campylobacter and E.coli. It can also delay fruit ripening and help stop vegetables such as potatoes and onions from sprouting.

What is food irradiation?

Food irradiation is a processing technique that exposes food to electron beams, X-rays or gamma rays. The process produces a similar effect to pasteurisation, cooking or other forms of heat treatment, but with less effect on look and texture. Irradiated food has been exposed to radioactivity but does not become radioactive itself.

Food absorbs energy when it is exposed to ionising radiation. The amount of energy absorbed is called ‘absorbed dose’, which is measured in units called grays (Gy) or kilograys (kGy), where 1kGy = 1,000Gy. The energy absorbed by the food causes the formation of short-lived molecules known as free radicals, which kill bacteria that cause food poisoning. They can also delay fruit ripening and help stop vegetables, such as potatoes and onions, from sprouting.

Is food irradiation safe?

Decades of research worldwide have shown that irradiation of food is a safe and effective way to kill bacteria in foods and extend its shelf life. Food irradiation has been examined thoroughly by joint committees of the World Health Organization (WHO), the United Nations Food and Agriculture Organization (FAO), by the European Community Scientific Committee for Food, the United States Food and Drug Administration and by a House of Lords committee. In 2011, the European Food Safety Authority reviewed the evidence and reasserted the opinion that food irradiation is safe.

Does food irradiation change the food in any way?

All food preservation techniques cause chemical changes in food – that is how they work. The changes caused by food irradiation (for example the production of free radicals) are similar in nature and extent to those caused by other preservation techniques, such as cooking, canning and pasteurisation. There may be some vitamin loss but this would occur with any other preservation technique or even just long-term storage. There is no evidence that any of the changes caused by food irradiation pose a risk to the health of consumers.

The law covering food irradiation states that irradiation can only be used where it is of benefit to the consumer. A company that wants to irradiate a food product, has to be able to show that the benefits of irradiation (for example reducing the risk of foodborne illness) outweigh any negative aspects (for example the loss of some vitamins). This will vary between different foods and means that the use of food irradiation is more suitable to some foods than others.

What methods of food irradiation are permitted?

The Food Irradiation Regulations allow for four methods of irradiation which are as follows:

  • gamma rays from the radionuclide cobalt-60
  • gamma rays from the radionuclide caesium-137
  • X-rays generated from machine sources operated at or below an energy level of 5MeV
  • electrons generated from machine sources operated at or below an energy level of 10MeV

How do I know if a food has been irradiated?

All foods which have been irradiated must be labelled as ‘irradiated’ or ‘treated with ionising radiation’. Where an irradiated food is used as an ingredient in another food, the words ‘irradiated’ or ‘treated with ionising radiation’ should appear next to the ingredient in the list of ingredients.

When irradiated food is not pre-packed these same words shall appear together with the name of the product on a display or notice above or besides the container in which the products are placed.