Frequently Asked Questions
Q: What is food irradiation?
Food irradiation is a physical treatment of food involving very large doses of ionising radiation to produce changes in food which are considered desirable.
Q: What is food irradiation used for?
The technology is promoted for preserving food and improving the safety of food. Food irradiation can be applied for the following purposes:
- To inhibit the sprouting of some root vegetables eg potatoes and onions
- To delay the ripening and ageing of some fruits and vegetables eg strawberries
- To kill or sterilise some insects and parasites that infest food eg grains, dried fruits, vegetables, nuts and meats
- To reduce the levels of spoilage bacteria on some foods, such as fruit, seafood, poultry and meat, enabling them to have a longer shelf-life
- To reduce the levels of viable food-poisoning bacteria on seafoods, poultry, meat and spices
Q: How is food irradiated?
Radiation for treating food can be sourced from machine generated electrical energy or from radioactive materials. There are three main methods to irradiate foods:
- High voltage electricity: electric and magnetic fields are used to accelerate electrons to high speeds and these can be used to bombard food.
- X-rays: the accelerated electrons can be made to strike a metal target and so be converted into x-rays which are then applied to the food - much like the equipment used in hospitals or dental surgeries, but larger.
- Radioactive materials: food is exposed to radioactive materials, usually cobalt-60 and occasionally caesium-137.
Q: Who is in favour of food irradiation?
The food industry and national governments have shown little interest in financing the research needed to convince governments that the technology is safe. To overcome international inertia, the International Atomic Energy Association (IAEA) established a Joint Expert Committee on Food Irradiation (JECFI) with the UN Food and Agriculture Organization (FAO) and the World Health Organization (WHO).
The IAEA has the UN mandate to control and develop peaceful uses for atomic energy. It collaborates with the FAO on uses of radiation in food and agriculture. Food irradiation was an important area of development as it could use waste and by-products from the atomic energy programme.
Since 1983, the promotion of food irradiation has been led by the IAEA/FAO International Consultatvie Group on Food Irradiation (ICGFI). Late in 1986, this Consultative Group convened a task force meeting or public relations and marketing experts to advise on how best to promote acceptance of irradiation.
The key elements involve convincing the world's public that irradiation is vitally necessary to deal with two critical food problems - food poisoning and world hunger. The strategy calls for concerted efforts to promote acceptance of irradiation by governments, industry, non-governmental organizations and consumers.
Q: Who is concerned over food irradiation?
Environment, consumer, women's, public health, trade union and some food industry organisations have rejected the arguments put forward for irradiation. In 1987 the World Congress of Consumers Organisations unanimously called for a moratorium on any further use or development of irradiation until a number of key issues were resolved. In 1988 an international UN conference failed to get agreement from participating countries on promoting acceptance of irradiated food.
Concerns of consumer and environmental organisations were taken up by a number of government delegations. A proposal to endorse the statement that there were 'no unresolved safety issues' had to be withdrawn. Several major countries dissociated themselves from the final resolution.
Q: Is irradiated food radioactive?
Just as people are not made radioactive by chest x-rays, so irradiated food is not radioactive. Provided the limitations on the energy of the radioactive sources are adhered to, there should be no significant risk of the food being made radioactive. Bombarding food with high-energy radiation can cause some elements within the food to become radioactive, however at the levels applied in food irradiation the amount of radioactivity created should be very small and die away rapidly.
The UK Advisory Committee suggests that, as a precaution, food should be stored for 24 hours after irradiation before it is eaten. After this time has elapsed any residual radiation would be undetectable against the 'background' level of radioactivity in food.
Q: Is irradiated food safe and wholesome?
The 1997 Joint FAO/IAEA/WHO Study Group on High Dose Irradiation concluded that 'food irradiated to any dose appropriate to achieve the intended technological objective is both safe to consume and nutritionally adequate'. The Study Group also concluded that 'no upper dose limit need be imposed' as 'irradiated foods are deemed wholesome throughout the technologically useful dose range from below 10kGy to envisioned doses above 10kGy'.
Unresolved consumer issues:
- Nutrient loss: Food irradiation can result in loss of nutrients, for example vitamin E levels can be reduced by 25% after irradiation and vitamin C by 5-10%. This is compounded by the longer storage times of irradiated foods. This is not in the interest of consumers, least of all those in impoverished nations or sections of societies already struggling to obtain adequate nutrition.
- Radiolytic contamination: Irradiation of food produces chemical changes. The result is a wide variety of radiolytic products. There is considerable controversy over the safety of these products, over how they might affect the people who eat them and future generations. Some of these chemical changes are known to be harmful, both mutagenic (altering genetic structures) and carcinogenic (causing cancers). There is controversy over the amount of research being undertaken to study these chemicals, and of the bias and quality of past studies which are used as a basis for official opinions on safety. One recent study found that hydrocarbons can form from an irradiated egg's natural fats. Some hydrocarbons can cause allergenic reactions while others are known carcinogens, however there do not appear to have been any tests undertaken of the hydrocarbons which formed in eggs.
Q: Are irradiation plants safe?
In recent decades incidents involving worker exposure to dangerous levels of radiation have occurred in the USA, Norway and Italy. In other incidents radioactive leaks have contaminated the areas surrounding irradiation plants costing millions of dollars to clean up. There have been cases of the theft and melting down of cobalt-60 sources in Mexico and Brazil, illustrating how easily widespread radioactive contamination can occur. The plants at which these incidents took place were built and operated under the internationally agreed system of regulation and control.
The prospect of increasing numbers of plants built across the world, in some cases in regions where regulatory controls may be even more difficult to enforce, poses very real risks.
Q: Are there wider environmental implications of food irradiation?
Food irradiation supports the trend towards globalisation through supporting centralised mass production and distribution of foods worldwide. Prolonged shelf life allows foods to be transported over greater distances contributing to increased fuel consumption and air pollution, more road accidents, socio-economic decline among small-scale local farmers and loss of wildlife habitats to industrial farming and road construction.
Q: How is irradiated food identifiable?
EC Directive 1999/2/EC requires all foods, or listed ingredients of food, which have been irradiated, to be labelled with the words 'irradiated' or 'treated with ionising radiation'.
Q: Is it permitted for food labelled as 'organic' to have been irradiated?
EU Regulation 2092/91 prohibits the irradiation of organic foods. This applies throughout the member states of the European Union.
Q: How will I know if restaurant food contains irradiated ingredients?
When food is not pre-packed and is sold for immediate consumption (for example in restaurants), the indication of irradiation must be marked or labelled on the menu, notice, ticket or label that the customer can see when choosing the food. Use of the term 'may contain' is no longer permitted.
Q: Can unlabelled irradiated food be identified by the consumer?
The taste, smell, texture and appearance of irradiated foods are usually no different to the same non-irradiated foods. Therefore in most cases consumers cannot identify an irradiated food if it has not been properly labelled as such.
Q: Can unlabelled irradiated food be identified by the regulators?
Most irradiated foods or foods containing irradiated ingredients can today be identified using specialised detection equipment and techniques.
When minerals (such as those found in shellfish or spices) are irradiated they take on energy. This energy can be released using physical methods such as heating the product and measuring the light released. This is thermoluminescence testing, favoured by the UK's Food Standards Agency (FSA).
Photo-stimulation is another method of detection, developed by Dr David Sanderson of the Scottish Universities Environmental Research Centre. Photo stimulation releases stored energy by an optical technique, using infrared radiation to detect blue and ultraviolet light emissions and detect single photons. The advantage of this technique is that it is cost-effective, sensitive to even minuscule quantities of an irradiated product and very quick - an initial positive or negative reading can be obtained in under a minute, indicating whether further testing may be necessary.
It is common practice to combine thermo-luminescence and photo-stimulation testing to ensure reliability.