Food Irradiation

FOOD IRRADIATION

What is Food Irradiation?

In the South African context, Food Irradiation is the treatment of a food with very short light or radio waves, in order to improve its safety, acceptability or shelf-life. These waves are two to three times shorter than waves that are produced in domestic ovens which cook food and they have the effect of pasteurizing or sterilizing the food rather than cooking it. Sometimes this process is known as “radurizing” or “radurization”. Scientifically, waves of different lengths, whether they be used for radio communication, cooking, vision or X rays, all form part of what is known as the spectrum of electromagnetic radiation.

Gamma rays occur as the shortest waves in this spectrum and it is these that are used to irradiate food. The rays penetrate deep into the food and because biological cells are sensitive to irradiation, the process is well suited to killing undesirable bacteria and insects. It can also be used to arrest the sprouting of potatoes, etc.  The rays are produced by a specially prepared metal known as cobalt 60 and are used under strictly controlled conditions, at lower dosages, to pasteurize food and at higher dosages, to sterilize medical equipment.

Why is food Irradiated?

1. To eliminate or reduce the number of disease-causing bacteria and other harmful organisms such as salmonella, E-coli, listeria and campylobacter.
2. To replace potentially harmful chemical fumigants when used to eliminate insects from maize, wheat, spices etc.
3. To meet quarantine requirements for international trade in fresh fruits and vegetables.
4. To extend the shelf-life of fresh fruit and vegetables, meat and poultry and so that these products can be stored for longer.

Is Irradiation Safe?

Food irradiation technology is probably the most exhaustively researched food processing method ever used. Scientists have studied food irradiation for more than 50 years and have concluded that it poses no health risk. The immense body of evidence is unanimous in support of irradiation as a safe and effective method for treating food.
The process is endorsed by the World Health Organisation (WHO), Food and Agriculture Organisation (FAO), the American Medical Association and the American Public Health Association and the US Food and Drug Administration (FDA). In South Africa the process is approved and supported by the Department of Health.
Irradiation of the human body by excessive quantities of light can cause sun burn and in a similar manner excessive quantities of Gamma rays are harmful to humans, as well as bacteria and insects. However, one should remember that gamma rays are also used to treat some cancers.

Frequently Asked Questions
 
Are Vitamins lost during the process?
There may be a reduction in the vitamin content during the process but this would be no worse than the loss during canning, drying, freezing or cooking. Spices are the food products that are the most commonly irradiated and because they are eaten in small quantities, any loss of vitamins would not be meaningful.  

Can irradiation make bad or unsafe food good?
Spoilt food can not be improved by irradiation. There is no substitute for good manufacturing process and good hygiene practice. The process aids in ensuring that well prepared food is safe for the consumer. The Department of Health only approves the irradiation of good foodstuffs where there is a technological need. The Department of Health monitors this very carefully and undertakes regular visits to the food irradiation processors.

Does irradiated food become radioactive?
Foods exposed to Gamma radiation do not become radioactive. The gamma rays are electromagnetic rays and are not radioactive particles. During the irradiation process the food never comes into contact with the radioactive material, Cobalt 60, as it is contained in doubly encapsulated stainless steel rods.

 What are the most commonly irradiated food products?
The most commonly irradiated foods are herbs and spices which, due to the nature of the drying process and to the way they are grown, often have an unacceptably high bacterial load. If these products are not treated, all foods to which they are added also become contaminated. Hence, this technology is used both because it is necessary and because it is the most appropriate, from the food safety point of view. Imported fresh garlic and imported honey are also irradiated as this is required by the Department of Agriculture to protect the local environment from unwanted insects, to prevent the sprouting of garlic and to kill bacteria that could affect the local bee population.

Can all food products be irradiated?
No, products that have a high fat content, such as full fat milk powder, develop taints when irradiated. This is a similar reaction to the development of off notes in these products when exposed to light or heat for an extended period of time.

Are dangerous by-products formed in food by irradiation?
One of the most frequently posed questions is whether the irradiation process forms toxic byproducts by rearranging the molecular makeup of food.
It is very common for foods to contain byproducts as a result of processing. The taste of bread is significantly developed by baking as is the taste of meat from the “braai”. So, by-products due to processing are very commonly found in foods. However, it can be said that extensive studies have not identified any byproducts unique to irradiated foods and none that are harmful.

How is irradiation regulated in South Africa?

In South Africa, Act 54 of 1972, labeling regulations(R1600 of 1983) states that irradiated foodstuff may NOT be sold without the permission of the Minister of Health or the Director General. Irradiated food must also bear a label stating that it has been irradiated. In effect, the applicant has to show that there is a reasonable technological need, that the process does not present a health hazard, and is of benefit to consumers. Normally, the maximum permissible dose for a foodstuff is10 kiloGrey (kGy). Furthermore, in a complex food, if more than 10% by weight has been irradiated the food must be labeled as irradiated.

What is the FACS position?

Limited irradiation of food is a very useful process for ensuring food safety. Where it is shown that there is a technical need and the process has been demonstrated to cause no damage to the food (loss of nutrients or production of toxins) and that the food is perfectly safe to eat, then FACS supports the use of the process with proper labeling. The fact is that the process is costly, so competition in the market place will limit the use of the process to those occasions were the need is great. FACS would also support any moves to ensure that manufacturers are complying with the law e.g. sampling and testing as in the EU where it has been shown that legal labeling compliance is sometimes lacking/neglected.

Further detailed information can be found under ‘irradiation’ at:

http://www.saafost.org.za/

http://www.ifst.org/site/cms/contentcategoryview.asp?category=126

http://www.fipaus.org/assets/FIPAqaSEP02.pdf