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The ABCs of X-ray food As Health Canada polls the nation about using radiationto help kill bacteria in our food, STEPHEN STRAUSS explains what this means for what we eat
By STEPHEN STRAUSS
Tuesday, December 10, 2002

Sometimes it seems as though life is a pop quiz in that science class you know you never studied enough for.

Starting this week, Health Canada will be asking people across the country what they think about using ionizing radiation to break down molecular bonds and create oxygen-free radicals that kill bacteria and insects in ground beef, poultry, prawns, shrimp and mangoes. Well, that's the kind of question the government might ask if all Canadians were scientists or academics.

What Health Canada is actually going to be looking for an answer to is something like: What do you think about using irradiation -- not "cold pasteurization" as some advocates in the United States would like -- to make certain foods less likely to poison you?

The inquiry is in part being undertaken because, while Canada has already approved irradiation for eight foodstuffs, the new list will likely represent the first time that many Canadians find themselves faced with a decision of whether or not to put anything irradiated in their stomachs.

This confusion has certainly been the case in the U.S., where upwards of 4,500 stores in sell irradiated food -- the lion's share of it being chopped meat. Furthermore, increasing numbers of restaurants, including 80 Dairy Queen stores in Minnesota, only sell irradiated hamburgers.

Nonetheless the instinctive first reactions of many people to the change, as reported in the American new media, would clearly send shivers up the spines of Canadian public-health officials. "I hope we don't start glowing in the dark after we have a cheeseburger," joked a 44-year-old Milwaukee homemaker as she munched on a free sample last month.

Others have a very different take. "Let me tell you how I cook my burgers. When they start to sizzle on one side, I turn them over. When they start to sizzle on the second side, I take them off the grill. This irradiated stuff will be great for me," perked a Pennsylvania shopper at a free food tasting.

These points of view clearly also play out in this country. In advance of the proposed changes, Agriculture and Agri-food Canada commissioned a poll on irradiation. After getting a brief description of the process, 54 per cent of those polled said they wouldn't buy irradiated food because of safety concerns, while 43 per cent said they would purchase it because the food would be safer.

Canadians' seeming ability to see the same process making their food both safer and more dangerous "tells you right away that there is a lot of misinformation or limited information," remarks Christine Bruhn, director of the Center for Consumer Science at the University of California at Davis and an irradiation proponent.

To give sense to what should be an informed public debate, we need to know what irradiation does, how it does it, what people fear and what they hope:

The history
In 1900, a professor in Massachusetts showed that if food was placed near radium, gamma rays would kill bacteria. Given the expense of radium at the time, this was more a scientific curiosity than a preservation strategy.

In 1921, another patent was granted for a technique that used X-rays to kill the Trichinella spiralis worm in pork.

Still, irradiation was largely unused until actively promoted by the United States after the Second World War as an offshoot of its development of nuclear energy. Now 52 countries have approved the sale of some form or another of irradiated food. Canada approved its first irradiated product -- potatoes -- in 1960.

In 1972, irradiated meat went to the moon with the Apollo 17 astronauts. NASA regularly gives space-shuttle astronauts specially prepared and then irradiated steaks, which the agency believes have a shelf life of two to three years.

How it works
While irradiation sounds like it must have a nuclear component, in a more generic sense, it applies to the effect of various high-energy particles generated by any number of sources -- radioactive cobalt, high-energy electricity, X-rays.

Basically food to be irradiated is placed on palettes and moved through a chamber where high-energy particles fly around. While each technique accomplishes the same end, they are not equally good for all things. The large numbers of particles generated by electron beams, for example, allows for the irradiation process to be completed in milliseconds.

Using the fewer gamma rays produced by radioactive processes can extend the treatment length to half an hour. However, the electrically generated particles are less energetic than gamma rays and can't even pass through thickish foods such as whole chickens and turkeys.

Generally, irradiating doses are less than 10 kiloGrays -- a unit of radiation-dose measure. The permitted level is one that kills most microorganisms, but doesn't necessarily leave the treated food completely sterile.

Changes in food after treatment
The most important irradiation change may be what doesn't happen. "It doesn't make the food radioactive, just as people don't become radioactive after receiving an X-ray or start glowing after they come in from the sunlight," says Donald Thayer, a U.S. Department of Agriculture researcher who has studied irradiation for decades.

At the dosages Health Canada is proposing, irradiation kills up to 99.999 per cent of potentially harmful bacteria like E. coli O157 and salmonella in meat.

And because bacteria is an intrinsic element in rotting, killing bacteria staves off putrefication. Irradiated chicken has a shelf life of 14 to 22 days -- two or three times that of non-irradiated fresh chicken. Hamburger, which rots in eight to 10 days, lasts up to 28 after being irradiated.

The treatment does alter the nature of irradiated food. The vitamin content goes down slightly. The process also creates what are termed "radiolytic compounds." For example, both benzene and formaldehyde are formed, as they are in many natural processes. Then there are cyclobutanones, potential carcinogens that appear in tiny quantities after food with fat in it is irradiated.

Very high dosages -- not those approved by Health Canada -- can cause a nasty sulphuric taste. And there can be subtle colour differences in uncooked meat. Chicken might hold a little more blush than normal. Chopped beef can get redder.

What irradiation doesn't do
It doesn't kill every bad microbe. Unfortunately, viruses -- as well as the prions that cause new variant Creutzfeld-Jacob disease, the human form of so-called mad-cow disease -- are so small that the energetic particles of irradiators generally don't hit and destroy them.

Irradiation also doesn't make food last forever. This is in part because some of the bacteria involved in rotting resist radiation at the dose levels Health Canada will approve.

Will irradiated food be labelled?
Yes. It will carry the international radura symbol, described as a broken green circle with stylized flower, that says the food has been irradiated.

Will it be very expensive?
A spokesman for the Dairy Queen restaurants in Minnesota say they pay about 10 cents (CDN) per pound more for meat they have irradiated in California. Based on the U.S. example, retail prices in a grocery market might be 25 to 40 cents a pound more costly.

What opponents worry about
Opponents like the Sierra Club of Canada worry that people won't see the limitations of what is being sold as a kind of food-safety cure-all. "My fear is that we are going to induce a sense of false security," says Dave Martin, nuclear-policy advisor for the Sierra Club.

More specifically, people have voiced these concerns:

The identifying labels will be left off irradiated foods in the rush to get things to market.

Cleaning up meat just before it goes to the consumer will encourage ranchers and slaughterhouses to allow dirtier practices. In the book Fast Food Nation, author Eric Schlosser quotes an agricultural journalist who says: "I don't want to be served irradiated feces along with my meat.

"Irradiation byproducts will be bad for us. No one has tested these things on humans over a long time.

The whole effort is a plot on the part of either big food companies or the nuclear industry to put something over on us.

What proponents argue
These include the World Health Organization, the American Medical Association, the American Dietetic Association and, by extension, grocery chains like Wegman's that have their own private-label brand of irradiated hamburger. They say:

Any nutritional losses will be inconsequential in a North American diet. "It has been estimated that, if all the pork in the United States were to be irradiated, Americans would lose only 3.2 per cent of the vitamin B1 in their diets," says Dr. Thayer.

"Irradiation converts small amounts of vitamin C in fruit to another equally usable form, so nothing is lost.

"Irradiated food will be labelled and there are numerous fingerprinting tests that can tell you if grocers are trying to pass the food on without letting you know.

There is no evidence that the food system will get dirtier after irradiation is adopted because severely contaminated food can't be returned to purity by irradiation.

Any bad chemicals that are created exist in very small amounts. Some, like benzyne and formaldehyde, appear naturally. Furthermore, Dr. Thayer, for example, has calculated that a 45-kilogram child would have to eat 163 hamburgers in a day to approach dangerous level of cyclobutanones. Ultimately, this is a technology that has been tested and retested for health effects for more than 50 years and nothing really bad has turned up.

Since not all the irradiators are produced by radioactive energy, it can't entirely be a conspiracy by the nuclear industry.

Selling irradiated food that claims to be safer than ordinary food actually creates a problem for agribusiness. "Quite frankly, saying something is safer than the rest of your products gives marketing people the horrors," Dr. Thayer says.

But most of all, one can't talk about any small disadvantages of irradiation without factoring in a huge positive change in public health.

In Canada, Health Canada spokesman Paul Myers says, "There are over a million cases of food-borne illnesses each year with an estimated economic burden of about a billion dollars.

"In the United States alone, it has been estimated that each year, 76 million people get sick with food poisoning.

Some 325,000 are admitted to hospital and 5,000 die. During the last two years, there were what amounted to 135 million bacteria-contaminated hamburgers and the chicken/turkey equivalent of about 27 million three-piece chicken dinners in the United States alone.

In theory, if you make chopped meat and chicken cleaner, you should make everything safer. Robert Tauxe, a researcher with the U.S. Centers for Disease Control, computes that if 50 per cent of poultry, ground beef, pork and processed meat were irradiated, it would prevent 900,000 cases of infection, 8,500 hospital admissions, 6,000 grave illnesses and 350 deaths in the United States.

The argument in the U.S. has been: Let the consumer decide.

Irradiated food meets ethnic cuisine
While Canada would only add the new irradiated food to the previously approved potatoes, onions, wheat flour, whole wheat flour, spices and seasonings, irradiation has been approved for nearly 250 different foodstuffs or specialty uses around the world. However, only a few hundred thousand tonnes of food is irradiated in total. This compares to a world production of about 1.7 billion tonnes of wheat, rice and corn.

Some of the odder irradiated edibles include: Nham, a raw fermented pork sausage eaten in Thailand, animal blood in Cuba, sweet potato wine in China, sorghum malt beer and milk-shake powder in South Africa, cassava chips in Brazil, buckwheat mush in the Ukraine, raw rabbit in Russia and red-pepper paste in Korea.

Making food safer isn't the only good irradiation may present the world. In March, scientists in India reported that they were able to dramatically reduce the flatulence of mung beans, chickpeas and black-eyed beans by irradiating them.