What is Food Irradiation?
In the South African context, Food irradiation is the treatment of food with very short electromagnetic waves, in order to improve its safety, acceptability or shelf-life. These waves are many times shorter than waves that are produced in microwave 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 "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 radio-isotope known as cobalt 60 and are used under strictly controlled conditions; at lower dosage, to pasteurize food and at higher dosage, to sterilize medical equipment.
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. (rancidity)
Are dangerous by-products formed in food by irradiation?
One of the most frequently posed questions is whether the irradiation process forms toxic by-products by rearranging the molecular makeup of food. At the doses used, the yield of radiolytic products is low and not of toxicological significance.
It is very common for foods to contain by-products 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.
How is irradiation regulated in South Africa?
In South Africa, Act 54 of 1972, labelling 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 is 10 kiloGray, (kGy).
What is the FACS position?
Limited irradiation of food is 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 labelling. 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 labelling compliance is sometimes lacking/neglected.
Further detailed information can be found under 'irradiation' at: http://www.ifst.org/food-irradiation
Reviewed for FACS by RBa (2016)