The century-old technology is routinely used on dried spices and flour in Canada and is approved to stop sprouting in onions and potatoes.
When food is irradiated, the food never touches the radioactive source itself. The food is briefly exposed to alpha or gamma rays that kill E. coli, salmonella and other microbes.
Public health authorities like the World Health Organization, U.S. Food and Drug Administration and Health Canada have all cleared food irradiation for safety but protests worldwide shut down plans to expand its use to meat.
After beef samples from the XL Foods plant in Brooks, Alta., tested positive for E. coli O157:H7 last month, microbiologists renewed their push for irradiation, a technology patented in 1905.
"Radiation's one of those things that's naturally, quote, dreaded," said Tim Sly, a professor at the School of Occupational and Public Health at Ryerson University in Toronto. "You just have to say the word and people take their loved ones and run to the hills, but in fact, it's not that much of a problem at all."
The risks associated with irradiation are "vanishingly small," compared with the risks associated with E. coli, Sly said.
Last year, one person in Canada died and a dozen were sickened from E. coli in walnuts. In 2006, five Americans died, including a two-year-old who ate spinach contaminated with E. coli.
In 2008, scientists at the U.S. Department of Agriculture reported that food irradiation will kill bacteria in salad greens. It won't work for products like bean sprouts — growing plants won't sprout if irradiated, Sly said.
How irradiation works
Sly compares the fears of irradiation to the initial aversion people had when microwave ovens were introduced.
Irradiating food does not change the taste, odour or appearance of the food and leaves no residue or radioactivity in the food, he said, although vitamins may be reduced slightly.
The Nordion Gamma Centre of Excellence in Laval, Que., irradiates spices, dried herbs and laboratory equipment in Canada and has international customers for food products.
Products are exposed to a radioactive source for a specific amount of time to either decontaminate it or sterilize it, said Carlo Coppola, the centre's director.
"It's a radioactive source, cobalt 60," Coppola said.
"It emits radiation, the product passes through this radiation field, depending on the dose required, it spends a specific amount of time in front of this field and then it exits. Once it exits, it can be handled right away, it does not become radioactive. And then it's packaged, put back on a palette and returned to the customer."
Since irradiation doesn't kill 100 per cent of micro-organisms, standard food preparation steps which include clean, separate, cook and chill, remain key to food safety.
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