Poultry irradiation: a food technology whose time has come

by OWEN ROBERTS

One of Canada's leading poultry irradiation proponents is Dr. John Lynch, a scientist and administrator at the University of Guelph's Laboratory Services, and a senior consultant with Fresh 'n' Safe, a Guelph-based company dedicated to food safety. Lynch and his Fresh 'n' Safe colleagues are studying the feasibility of bringing a food irradiator (cost: $6-$10 million) to southern Ontario, home of most food processing in Canada.

They've been at it for years. In 1996, Lynch submitted a proposal to Health Canada for approval to radiate poultry for sale in Canada. Years went by with no response. Then, as he was rummaging through his bills and junk mail a few weeks before this past Christmas there it was - a letter saying his request had (finally) received a "favourable recommendation" from the senior management committee of Health Canada's food directorate.

Lynch calls the approval a major development in Canadian food safety. He's convinced irradiation - which involves exposing food to small doses of radiation to kill many of the micro-organisms (such as bacteria and fungi) which can poison consumers - is efficient and effective. Irradiation works by either damaging the DNA of the microorganisms so they can't reproduce, or by causing their outer membranes to break down, so they die. As a result, it increases shelf-life appreciably. It's not unusual for irradiated strawberries to last up to three weeks in the refrigerator, compared to untreated samples that can rot in three days.

Lynch is not alone in his faith in irradiation. Although Canada has tiptoed around blessing the technology - despite the fact Canadians have been leaders in its development - it's a different story south of the border. The United States Department of Agriculture (USDA) says point-blank that irradiated food is safe to eat, having been evaluated for 50 years and approved in 37 countries for more than 40 food products. And it's not just American business interests that are prompting the USDA's supportive words: the process has also been endorsed by the United Nation's World Health Organization, Codex Alimentarius Commission and the American Medical Association.

The buy-in from the Americans has prompted 20 irradiation processing facilities to pop up in the United States. Tyson Foods, the world's largest integrated poultry company, is now publicly indicating that they are irradiating a small portion of their production. Tyson recently acquired IBP, the world's largest beef processor, which has contracted to have one or more electron beam systems integrated into its U.S. production lines. Lynch says that between poultry and beef, it's estimated more than 2,000 American retail outlets are carrying irradiated meat. Schwan's, the leading U.S. distributor of frozen foods, is now offering direct delivery of irradiated meat in 48 states.

A big plus for irradiation (besides the highly extended shelf life) is that it doesn't affect the taste or texture of food. In 1998, Lynch hosted a meeting of the Eastern Canada Farm Writers' Association, offering irradiated and non-irradiated strawberries to the 30 members in attendance. The difference was unnoticeable.

Nonetheless, the term "irradiation" scares the daylights out of some people, even though we probably eat irradiated food now, in some form - particularly spices, which are especially prone to harbouring microorganisms (spices are typically grown in tropical climates, picked wet, dried outdoors and then ground by hand).

In Canada, spices as well as onions, flour and potatoes are approved for irradiation, but only spice irradiation actually takes place here. However, if poultry is added to the mix, irradiation could take off. Poultry is a huge market (Ontario has about one-third of the nation's market), and retails for enough money to make investing in the process worthwhile.

Based on the U.S. experience, the process adds about five cents a serving to the cost of the product. But Lynch says that's peanuts compared to the cost of a lawsuit for food poisoning. Poultry is particularly susceptible to salmonella bacteria, and Lynch expects

institutions that handle huge quantities of food - hospitals, nursing homes, hotels and prisons, among them - to be eager to reduce their vulnerability and corporate liability. Indeed, U.S. hospitals already use irradiation to sterilize food for patients with weakened immune systems. Even some perishable food taken into space by astronauts is irradiated to eliminate disease-causing organisms. Says Lynch: "If governments think irradiated foods are safe enough to give to our brightest and best, then shouldn't they be good for the rest of us?"

At the same farm writers' meeting hosted by Lynch, Christine Mitchler, then chair of the Consumers Association of Canada's (CAC) national food committee, said she accepts the science that says irradiation is safe. But she's worried about consumers getting lazy about food safety.

"Food irradiation could be seen as a panacea or silver bullet," she warns. Instead of taking proper care to handle and process food, consumers might think standard safeguards are unnecessary. And that's a red flag: bacteria will still grow if the conditions are right, for instance when you go shopping on a hot day, leave your groceries in the trunk while doing other errands, then come home and start barbequing. Those are ideal growing conditions for bacteria, irradiation or not.

From a producer's perspective, Murray Booy of Aylmer says consumer acceptance is crucial for irradiation. Ontario, which has seen its share of Canadian production fall two per cent in the last six years, is unlikely to want to jeopardize that share further with a consumer backlash. The irony is that more and more product is going to the fresh trade, where irradiation has the potential to make the biggest difference in food safety.

"Labelling and education are huge factors," says Booy. "Chicken already has a good reputation for being safe, especially in Ontario, so the question is whether consumers require [irradiated product] and are willing to pay for it and use it. Confidence will have to build over time." BF
Contributing Editor Owen Roberts teaches agricultural communications and directs research communications at the University of Guelph.

Dairy-cow parasite sparks Ontario-wide study

By Kristy Nudds and Cheryl Rae

Parasitology Prof. Andrew Peregrine, Population Medicine Prof. Todd Duffield, and Jamie Hobson, a graduate student and practicing veterinarian in Elmira, Ont., have been investigating what's decidedly the number one cause of abortion in dairy cattle on the continent: Neospora caninum. They're examining the results of blood samples of about 5,200 cows from 90 farms in southern Ontario to determine the effect this parasite may be having on dairy cows here, about eight per cent of which have the infection.

"We've known about this parasite for about ten years, but up until one year ago, very little was known about its prevalence among Ontario dairy herds," says Peregrine.

Neospora caninum is transferred primarily from cow to fetus. It is believed to lie dormant in the central nervous system until a signal during pregnancy triggers its release. Besides having the potential to cause abortion and increase fetal losses, the parasite results in a higher amount of retained placentas, according to data from the Ontario study. If a cow is discovered to be infected, she is up to four times more likely to abort than if she was not infected. If calves born to infected mothers survive, there is a high chance that they will be infected, too. The risk of abortion is greatest for first-calf heifers and decreases with each successive pregnancy.

Research on a large dairy operation in California found that first-lactation cows carrying the parasite produced 1 kg less milk per day. The OVC study has not indicated this kind of results so far, says Hobson, but he is not ruling it out. "If it produces similar results," he adds, "then the parasite will have a greater impact than first believed."

However, there's no question it is present here. The OVC study shows N. caninum varied among the farms visited, with some herds having no cases, while as many as 78 per cent of cows in other herds were found to be infected. The researchers will be examining whether or not the wide range of results found in the study has been influenced by differences in management practices or geographic location.

Hobson advises farmers experiencing an abortion rate of greater than five per cent of pregnancies to have at least a part of their herd tested for the parasite (blood tests cost approximately $6 per head). If abortion occurs, it is crucial that the fetus and placenta are kept, and that a blood sample be taken, he says. All of these must be sent to a diagnostic lab to determine if the parasite is behind the abortion.

Hobson also recommends keeping cows away from the afterbirths, and keeping dead calves and afterbirths out of the reach of dogs. It's possible for dogs to transmit N. caninum to the herd, but the researchers warn that the folklore-like stigma surrounding their involvement is generally exaggerated.

"Some farmers in Canada and the United States have been going to extremes and getting rid of their dogs," says Peregrine, "but there is no reason for this on most farms. The main reservoir for the parasite is the cows themselves. Dogs generally play a very minor role in parasite transmission."

Hobson is also analyzing the relationship between Ontario Dairy Herd Improvement production data and the blood sample results. As well, work is also being done to determine if the parasite has been a cause of preferential culling in Ontario herds.

Final analysis of the data collected will be completed by this fall. The researchers hope it will provide them with solid information to help producers understand the best way to manage N. caninum. But whatever the analysis reveals, the big question will still be what producers should do.

The researchers say that while selective culling of seropositive animals is the primary method for controlling the parasite, producers should note that these animals do not need to be culled until at least the end of their current productive lactation. BF

This research was sponsored by the Ontario Ministry of Agriculture, Food and Rural Affairs, the Ontario Cattlemen's Association, Provel (a division of Eli Lilly Canada Inc.) and the Dairy Farmers of Ontario.

The writers are agricultural communication students at the University of Guelph.