Food irradiation -- a gift horse?

Canadians who were alarmed by the recent outbreak of E. coli sickness from beef should know that pathogen contamination in processing plants cannot be prevented. If we really want to prevent outbreaks, we have to look at expanded use of irradiation.

Health Canada data show food-borne illness is a close second to diabetes in terms of pressure on the health system. Accurate yearly analysis is not possible because food-borne illness is voluntarily and inconsistently reported by provinces and territories to the national reporting system.

Available data show little progress in resolving challenges associated with contaminated food either here or in the U.S. There is concern -- because there is no strategy to implement interventions or ability to evaluate their effectiveness -- that safe food in Canada is more by accident than by design.

The provinces and territories are finally establishing performance objectives limiting frequencies of poultry carcass contamination by Salmonella and Campylobacter. Unfortunately, compliance with these standards cannot be measured against changes in rates of human illness from poultry consumption because a yardstick does not exist. It is these kinds of well-intentioned but unco-ordinated programs that drain resources, spawn complacency and ultimately obstruct our ability to understand the root causes of the problems and fix them.

The food we eat is often contaminated by pathogens that do not cause symptoms in plants and animals, but make people sick. In recent years, 25 per cent of food-borne illnesses in the U.S. have come from crops contaminated by Salmonella, toxigenic E. coli and Listeria monocytogenes. In contrast, just 25 years ago produce was believed responsible for less than one per cent of food-borne illnesses.

While there is now better reporting and detection, the rise in frequency of illness is due also to changes in production and processing methods, larger and more integrated farms and changes in pathogen occurrence.

The economics of plant agriculture have meant animal manures are used more often in production. Since the outbreak of mad cow disease 10 years ago, farmers can't feed rendered cows as an animal feed, so they've turned to oilseed protein as a substitute. Animal manures and oil seed protein (soy, canola) are frequently contaminated by Salmonella and often by toxigenic E. coli, and thus they are continuously recycled in the farm environment where they are accumulating.

Organic and local production cannot protect us because this recycling is common to them. Although meat processing plant contamination by Listeria can be controlled, Listeria on produce and Campylobacter on poultry are not well understood or controlled in Canada, meaning they have free access to our kitchens.

Food irradiation is the most intensively studied of all technologies used to process food. In spite of what its detractors may contend, evidence from over 100 years of study show it can effectively reduce pathogen contamination of foods at levels that do not create toxicity, affect its wholesomeness or nutritional adequacy.

Canadian approvals have been in place since the 1960s for treatment of potatoes, onions, wheat flour, spices and dry seasonings. Specific approvals for food irradiation exist in over 55 countries, including the EU.

In the U.S., irradiation of mangoes and a variety of produce, shrimp, poultry and red meat at specified doses is permitted and about seven to eight million kilograms of irradiated ground beef is consumed annually.

Irradiation of produce at low dose in international trade is gaining acceptance, largely because it replaces pesticide use for quarantine control of insects.

Obstacles to irradiation adoption include its availability, costs of the technology, and concern about public perception.

Irradiation will not hide incompetence in industry practice and electron beams do not generate radioactive waste. Slow adoption of food irradiation is mainly due to psychological and political barriers.

A majority of Canadian consumers now support food irradiation and both the Canadian Food Inspection Agency and Health Canada have clear policies that favour its expanded use to improve food safety. However, there has been no change in Canadian food irradiation legislation since 2002.

Expanded zero tolerance legislation for pathogens like toxigenic E. coli in raw foods is not the solution; the only certainties with this approach are more testing and greater waste with nothing left to eat. We are at a point of diminishing returns in food safety measures, and the last remaining viable solution to pathogen contamination is irradiation. If poultry alone were irradiated to eliminate Campylobacter (the major cause of food-borne illness) and Salmonella, data show that food-borne illness in Canada would be reduced immediately by 25 per cent.

Concerns regarding expanded use of food irradiation require transparent consideration. However, it is clear that there is no need to reinvent studies to show its generic safety and efficacy.

Indeed, organic farmers should reconsider their opposition given the equal risk that an organic product might be involved in the next Salmonella recall. There is no room for complacency either; it is time to use food irradiation for our collective good.

Rick Holley is a professor in the department of food science at the University of Manitoba.

Republished from the Winnipeg Free Press print edition November 10, 2012 A14