Friday 13 November 2009
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.
Food irradiation is a processing technique that exposes food to electron beams, X-rays or gamma rays, and 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, and with some food, such as spices that are dried in the sun, irradiation kills bacteria without changing their flavours or aromas.
Food absorbs energy when it is exposed to ionising radiation. The amount of energy absorbed is called 'absorbed dose', which is measured in units of Gray (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.
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 is no evidence that any of the chemical changes caused by food irradiation pose a risk to the health of consumers.
It is required that all foods, or ingredients of foods listed on the label, which have been irradiated, are labelled as 'irradiated' or 'treated with ionising radiation'. 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.
A number of tests have been perfected and validated for the detection of different irradiated foods, including herbs and spices, poultry and meat containing bone and products containing fats. These tests have been verified in trials involving laboratories throughout Europe. Regular surveys are undertaken by the Food Standards Agency. Further research is currently taking place to extend the range of irradiated foods which can be detected.
Many foods, however, contain ingredients from different sources, 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’.
Current national regulations allow for the irradiation of seven categories of food: fruit, vegetables, cereals, bulbs and tubers, spices and condiments, fish and shellfish and poultry. However, only one licence for the irradiation of a number of herbs and spices has so far been granted.
The European Community has produced a list of irradiated food 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. More information on food irradiation in EC countries can be accessed through the European Commission website.
In the US a variety of foods have been approved for irradiation, for several different purposes. The current list includes wheat, potatoes, fruit and vegetables, herbs and spices, pork, poultry and beef.
Other countries irradiate food, including Canada, France, the Netherlands, Indonesia, Israel, Thailand, Russia, China and South Africa.
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.
One of the practical aspects of food irradiation is that is 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.
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 Standards Agency is the national licencing and inspection authority for food irradiation facilities in the UK. Food irradiation can be allowed under the Food Irradiation (England) Regulations 2009, with parallel legislation in Scotland, Wales and Northern Ireland.