Irradiated food

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.

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. It is used in many parts of the world because it is an effective way of killing bacteria with some food, such as spices that are dried in the sun.

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 1 kGy = 1000 Gy. The energy absorbed by the food causes the formation of short-lived molecules known as free radicals, which kill micro-organisms and also interact with other food molecules.

Free radicals are formed by almost all food processing techniques, including cooking, chopping and grinding. Ionising radiation also kills bacteria directly by affecting their DNA.

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.

All food preservation techniques cause chemical changes in food – that is how they work. The changes caused by food irradiation 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 regulations that cover food irradiation in the UK, state 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 food-borne illness) outweigh any negative aspects (for example the loss of vitamins). This will vary between different foods and means that the use of food irradiation is more suitable to some foods than others.

There is no significant difference to the smell, taste or appearance of food that has been irradiated. This is due to the fact that very small levels of energy are absorbed by the food during irradiation.

No, irradiated food has been exposed to radiation but is not contaminated with radioactivity.

Many foods, however, contain ingredients from different sources which may have been irradiated, such as curry powder. The law states that if a permitted irradiated food is mixed with a non-irradiated food, the resulting product has to be labelled as either ‘irradiated’ or 'treated with ionising radiation'.

Food irradiation is a consumer’s choice and labelling issue and not a food safety issue. The Food Standards Agency recognises irradiation as a safe processing technique and undertakes safety inspections of the only irradiation facility in the UK. The Agency carries out regular surveys to ensure that products are correctly labelled.

The Food Irradiation (England) Regulations 2009 list the seven categories of food which may be irradiated. For each category of food the 'maximum overall average dose' that can be used is specified in units of kilograys (kGy):

• fruit, 2kGy
• vegetables, 1kGy
• cereals, 1kGy
• bulbs and tubers, 0.2kGy
• dried aromatic herbs, spices and vegetable seasonings, 10kGy
• fish and shellfish, 3kGy
• poultry, 7kGy

These categories of food can also be irradiated and used as ingredients in other food products.

There is only one food irradiation facility in the UK, and it is licensed to irradiate a range of dried aromatic herbs, spices and vegetable seasonings.

In the UK, local authorities and port health authorities are responsible for controlling imports of irradiated foods, including appropriate testing. Certain foods that have been irradiated may be imported into the UK, as long as they comply with certain rules. The Food Irradiation (England) Regulations 2009 set out the requirements for producing, importing and selling irradiated food in the UK. The food must come from an approved facility and must have the correct documentation to accompany it. There is also parallel legislation in Wales, Northern Ireland and Scotland.

See the link below for more information about the importation of irradiated foods.

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

• gamma rays from the radionuclide cobolt-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

Foods are irradiated in authorised irradiation facilities which must be licensed, regulated and subjected to strict safety inspections by the Food Standards Agency. Irradiation facilities are of mainly two types: gamma sources and electron beams.

Foods must be irradiated in authorised food irradiation facilities which are subjected to strict safety inspections. There is currently only one licensed food irradiation facility in the UK. There are over 20 facilities in other European Union (EU) member states and ten outside the EU (three in South Africa and India, two in Thailand and one each in Turkey and Switzerland).

The Food Standards Agency is the national licensing and inspection authority for food irradiation facilities in the UK. In EU member states the competent authority will approve facilities in their country. Food irradiation facilities in EU countries must be approved by the European Commission.

It is required that all foods which have been irradiated, are 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 and is sold for immediate consumption (for example, in restaurants) it must be marked or labelled on a menu, notice or ticket that the consumer can see when choosing the food.

There have been a number of tests perfected and validated for the detection of different irradiated foods, including herbs and spices, poultry and meat containing bone and products containing fats.

Although the tests can show if a food has been irradiated, they are unable to tell you what dose the food has received. This is one of the reasons why food irradiation facilities must be licensed to ensure they can demonstrate accurate measurements of the dose they give to the food.

There are ten European Committee for Standardisation (CEN) standard tests. For information on these tests, please see the link below.

Trading Standards Officers take samples of products on sale and take action where illegally irradiated or mislabelled products are discovered. Results from these samples (and equivalent samples taken in other EU countries) are provided in the European Commission (EC) reports, which can be found by referring tovia the link below.

The European Community has produced a list of irradiated foods that can be freely traded across the EU boundaries. The list is not complete and at present it has only one food group: dried aromatic herbs, spices and vegetable seasonings.

In addition to this group, countries within the EU may permit the irradiation of other categories of food. This list of foods varies between different countries, for example France and the Netherlands allow the irradiation of frog’s legs which is not permitted in the UK. More information on food irradiation in EU countries can be found on the European Commission website.

Many countries outside of the EU allow certain foods to be irradiated, including the USA, Indonesia, Israel, Thailand, Russia, China, South Africa, India and Turkey. However, only those with irradiation facilities approved by the European Commission can import these foods for sale into the UK.

Yes, it is. X-ray scanners used at airports for baggage control operate at very much lower energy and give rise to radiation levels very much lower than radiation sources used in food irradiation facilities. The radiation doses used to process food can be as high as 10,000 gray, whilst X-ray scanners operate at less than 0.5 gray. It is very difficult, if not impossible, to detect changes to food once it has been through an X-ray scanner.

The Food Irradiation Regulations 2009 specifically excludes X-ray surveillance devices which impart a radiation dose of less than 0.5 gray and operate at less than a maximum energy of 10 MeV (for example the ones used in ports and airports, which would include those used for commercial cargo). If the devices operate above these levels, they fall within the scope of food irradiation legislation, but the FSA is not aware of any devices currently in use which do exceed these limits. In fact many of these X-ray machines (at airports for example) operate at such a low dose that they don't affect photographic film.

There is no requirement for a licence to handle irradiated foods. If you are storing or transporting irradiated food for the purpose of sale and you are not licensed (in other words you are not the food irradiation facility), then you must ensure that the correct documentation accompanies the food. The information required on this documentation is specified in the regulations, but is essentially information about how and where the food was irradiated, which will be supplied by the irradiation facility. Documentation containing this information must accompany the food up until the point where it is sold to the ultimate consumer or catering establishment.

One of the practical aspects of food irradiation is that it can be used on food already in its final package. The effect of irradiation on plastics and other packaging was investigated in the 1960s and early 1970s, in order to identify safe packaging materials for use in the space programme. Only a few materials have been approved for use in packaging food that is to be irradiated and many more need to be tested if food irradiation is to become widely used and the Agency is carrying out research looking into this (see link below).