Food irradiation

Food irradiation is a processing and preservation technique that produces results similar to freezing or pasteurization. During the procedure, food is exposed to doses of ionizing energy, or radiation.

At low doses, irradiation extends a product’s shelf life. At higher doses, the process kills insects, molds, bacteria and other potentially harmful micro-organisms. Several decades of scientific research indicate that food irradiation is a safe and effective form of processing, and it has been approved for use in many countries around the world.

In many places only a limited range of foods has been approved for irradiation by food regulators, typically items such as herbs and spices, herbal infusions and some tropical fruits. For each approved food, regulators have established that there are no safety concerns and no significant nutritional changes as a result of irradiation. Irradiated foods are clearly labeled so that consumers can make an informed choice.

Irradiated food is not radioactive#

There is a common misconception that irradiated food is radioactive. The radiation used to process foods is very different from the radioactive fallout that follows, for example, a nuclear accident. In food processing, the radioactive sources that are permitted do not generate gamma rays, electrons or x-rays of high enough energy to make food radioactive, and no radioactive energy remains in the food after treatment.

Internationally recognized scientific and health bodies, including the World Health Organization, support food irradiation as a safe technology.

How irradiation works#

Food is exposed to ionizing radiation, either from gamma rays, a high-energy electron beam or powerful x-rays.

Gamma rays and x-rays are a form of radiation that shares some characteristics with microwaves, but with much higher energy and penetration. The rays pass through the food much as microwaves do in a microwave oven, but the food does not heat up to any significant extent, and exposure does not make the food radioactive.

Electron beams and x-rays are produced using electricity, which can be switched on or off, and they do not require radioactive material. In every case, the organisms responsible for spoiling food – including insects, molds and bacteria, among them some important food poisoning bacteria – can be killed. Irradiation cannot, however, kill viruses.

Benefits of food irradiation#

Some of the benefits of this processing technique include:

• a reduced need for toxic chemical treatments, such as those used to disinfect imported fruits, grains and vegetables
• a reduced need for fumigants, some of which deplete the ozone layer
• reduced sprouting in produce such as potatoes, onions and some herbs
• extended shelf life and less food spoilage
• a reduced risk of food-borne illness caused by micro-organisms
• less need for some pesticides, preservatives and antioxidants
• a lower risk of importing or exporting insect pests hidden inside food products

Some foods, such as dairy foods and eggs, cannot be irradiated because the process changes their flavor or texture. Fruits, vegetables, grain foods, spices and meats such as chicken can be irradiated.

Effects on nutrients#

Irradiation causes only minimal changes to the chemical composition of food. It can, however, reduce the level of some B-group vitamins in certain foods. This loss is similar to the losses that occur when food is cooked or preserved by more traditional and widely accepted methods, such as canning or blanching.

Common concerns#

People have raised a number of concerns about food irradiation, including:

• Radioactivity – a belief that irradiated food is radioactive and therefore harmful. In fact, irradiated foods do not become radioactive, and extensive testing has shown that irradiating food is as safe as canning, pasteurizing and freezing.
• Lack of choice – many consumers want to be able to choose between irradiated and non-irradiated foods. This is managed through mandatory labeling.
• Effects on food hygiene – a concern that wide use of irradiation may lead to less careful food hygiene and handling. Irradiation is not a substitute for good hygienic practices.
• Loss of natural warning signs – a concern that irradiation could make it harder to tell whether food is old or has gone “off” because normal indicators such as smell or mold are reduced.
• Not for the consumer’s benefit – a concern that irradiation is driven by market needs rather than consumer demand.

Labeling of irradiated foods#

If a food has been irradiated, or contains irradiated ingredients or components, it must carry a statement that the food, ingredient or component has been treated with ionizing radiation. Where a product has no label, such as whole fruit sold loose, this statement must be displayed close to the food. Irradiated foods may also be marked with a symbol called a “radura”, the international symbol for irradiation.

Proper food handling is still needed#

Food irradiation should only be used where it meets a genuine technological need or serves a food safety or food hygiene purpose. It does not replace the need for correct food handling in industry and in the home. For example, a few bacteria may survive the irradiation of meat; if that meat is then left unrefrigerated, the surviving bacteria could still multiply and cause food poisoning.

Key points#

• There is a common misconception that irradiated food is radioactive.
• No radioactive energy remains in the food after treatment.
• Some foods, such as dairy foods and eggs, cannot be irradiated because it changes their flavor or texture.
• If irradiated meat is left unrefrigerated, surviving bacteria could still multiply and cause food poisoning.

Where to get help#