New technologies to help ensure the safety of the food supply are
being discovered all the time. The emergence of new types of harmful
bacteria and the evolution of older types mean that scientists need to
continuously work to improve food safety techniques and ensure the
safety of our food supply.
One of the more recent applications to ensure the safety of our food
supply is food irradiation. Many health experts agree that food
irradiation can eliminate many foodborne hazards and help ensure that
harmful organisms are not in the foods we buy. Irradiation is used to
destroy bacteria such as E. coli, Campylobacter and Salmonella,
all of which can cause human illness.
Irradiation is also used in a variety of non-food applications. Many
first aid dressings have been irradiated to destroy bacteria.
Irradiation is also used in cosmetics and pharmaceuticals to make them
safe from bacterial contamination.
What is food irradiation?
Food irradiation is the process of exposing food products to ionising
energy for a specified length of time. It is often called "cold
pasteurisation" because it kills harmful bacteria without the use of
heat.
Is food irradiation safe?
Yes. Food irradiation has actually been used since 1905 when the
first patents were allowed in the United Kingdom and the United States.
Since then, hundreds of studies have been reviewed by governmental
agencies charged with ensuring the safety of the food supply. It is one
of the most widely studied food-processing technologies available.
The World Health Organization (WHO) of the United Nations has
approved the safety of food irradiation and its use for a wide variety
of food products. Worldwide, 37 countries have approved food irradiation
for more than 40 food products. Organisations such as the American
Medical Association, the Scientific Committee of the European Union and
the US Food and Drug Administration also endorse the process.
More than forty countries have granted clearance or authorisation to
irradiate specific foods. The United States, South Africa, Belgium,
France, China and the Netherlands currently irradiate small but
significant volumes of food commercially.
In the United States, food irradiation is used to extend the shelf
life of a product and to kill bacteria. Food irradiation has been
approved for fruits, vegetables, grains, spices, eggs, poultry, beef,
pork and lamb.
Does irradiation make foods radioactive?
No. Irradiation is a process by which food is moved through a radiant
energy field however the food never touches the energy. The gamma rays
are similar to ultraviolet light or microwaves but are of much shorter
wavelength and greater energy. Gamma rays pass energy through food in
much the same way as microwaves however, in this case, the food remains
cool. The food is not made radioactive and no radiation remains after
treatment.
Food, which has been packed into containers, is exposed briefly to a
gamma ray source. The gamma rays passing through the food destroy
bacteria, other disease-causing organisms and insects. Just like
pasteurisation, food treated by irradiation is safer to eat. One of the
added benefits of irradiation is that it can be applied to both solid
and liquid foods unlike pasteurisation, which can only be applied to
liquids.
Different doses of ionising radiation can be used to achieve
different effects. For example, at low doses, irradiation is used to
lengthen the shelf life of foods. It has been used to delay the ripening
of fruits such as strawberries and limit unwanted sprouting in potatoes.
At higher doses, irradiation is used to reduce harmful bacteria in foods
such as poultry and dry herbs and spices.
Does irradiation change the nutritional value or flavour of foods?
Irradiation produces virtually no heat within food and does not
"cook" foods. Foods processed with irradiation are just as nutritious,
flavourful and wholesome as other foods.
How can I tell if a food has been irradiated?
Most countries that permit food irradiation require labelling to show
this is the case.
In America for example, US law requires that all irradiated foods
must be labelled with an international symbol for irradiation (the
radura). This is depicted by green petals in a broken circle and
accompanied by the words "treated by irradiation" or "treated with
radiation".
Is food treated with irradiation immune to infestation and
contamination?
Although food irradiation can reduce the risk of foodborne disease by
destroying bacteria and parasites, the process complements proper food
handling practices. It cannot enhance food that has deteriorated or food
that is of inferior quality, nor can it prevent contamination from
improper handling after irradiation.
As with any food product, food processors, service workers,
restaurants and consumers need to follow safe food handling and
preparation guidelines to ensure food safety. These safe food-handling
measures include:
- Frequently washing hands and preparation surfaces with hot, soapy
water.
- Separating raw and cooked foods to prevent cross contamination
(infestation or contamination spreading from one food to another).
- Cooking foods thoroughly.
- Refrigerating and storing foods properly.
