Irradiated food does not become radioactive, expert says

Food exposed to X-rays does not become radioactive, so it poses no radiation hazard after treatment, according to an answer by medical physicist Eyjólfur Guðmundsson published by mbl.is. Irradiation can destroy microorganisms and extend food’s shelf life.

Guðmundsson, who works for the Icelandic Radiation Safety Authority and is an adjunct at the University of Iceland, said there was no evidence that food irradiation harms nutritional value or quality more than other methods used to sterilise food and extend its shelf life.

Irradiation is used in food production to bring about changes, usually to preserve food for longer. It can be used to sterilise products, control pests and delay the ripening of fruit and vegetables. It is also used for quality control, such as detecting bones in fish on a conveyor belt. In those inspections, X-rays create images of the food’s internal structure, using less energy and lower radiation levels than sterilisation does.

For sterilisation, a dose high enough to cause lasting damage to microorganisms, including bacteria and mould, is applied. The process does not significantly heat the food. Research indicates that its effects on nutritional value are less than or comparable to those of canning and pasteurisation.

In Iceland, high-energy irradiation is permitted only for dried herbs, spices and vegetable seasonings, but no such activity takes place in the country. One advantage of irradiation is that products can be treated after they have been packaged. The method has also long been used to sterilise consumer and medical products, including syringes and disposable gloves.