Food irradiation is back

By Dave Riley

Food irradiation is back on the menu. Australia's three-year moratorium on it expired on December 12. The National Food Authority will soon develop "standards on the process of treating food with ionising radiation to increase shelf life". What happens next is a purely political issue.

Food is irradiated by exposing it to gamma rays emitted by cobalt 60. The process kills bugs like fruit-fly and salmonella, and fungus; it also slows down the ripening process and thereby extends the food's shelf life.

Any radioactivity induced in foods by this process is quite small compared to that occurring through normal background radiation. The worry is not induced radioactivity but more substantial concerns.

While gamma rays will kill micro-organisms, they won't affect the toxins already produced in the food. Botulism (food poisoning), for instance, is caused by the toxins produced by the spores of Clostridium botulinum. Hence contaminated food may be sold minus the telltale signs by which we are normally warned. Gamma radiation also does not eliminate viruses from foods.

The choice of the food industry may in the end be determined by economics and image. Irradiation does not come cheap, and the increased cost will no doubt be passed on to the consumer. The consumer in turn is left to ask, "If they have to irradiate the food, what was wrong with it in the first place?"

This presents problems in determining an appropriate label for irradiated products. One African country employed the innocuous term "rad-purised" to overcome consumer resistance. In Britain food irradiation suffered a major image problem when consignments of seafood contaminated with sewage micro-organisms, and already rejected in another country, were bought up cheaply and irradiated in the Netherlands. With their lowered "bug count", they gained admission to Britain and commanded full price. This entrepot activity was called "sending the prawns on holiday to Holland".

A major factor driving the campaign for food irradiation is world trade. While universal acceptance of irradiated foods is a myth, the economic logic of it is excellent for the export industry. Irradiation eliminates many of the bugs, such as fruit fly, that are currently subject to quarantine in many countries. Irradiation is therefore equated with market access.

This is one of the reasons the World Health Organisation has equivocated on the issue. It has also been accused of being in the pocket of the International Atomic Energy Authority, which stands to make a lot out of a generalised acceptance of food irradiation.

Nonetheless, in many Third World countries employing cobalt 60 to extend the use-by date of food is seen as cheaper than the expensive investment required to refrigerate produce in hot climates. Cuba, for instance, a tropical country with minimal capital reserves, is reputed to favour food irradiation for this reason.

Three years ago the debate on this issue was full on. The moratorium has diffused the polemics. If we don't want "fresh is best" to be an archaic concept, then the ban on irradiated foods should be extended.

From GLW issue 92