TORONTO - While officials desperately try to pinpoint the cause of a deadly E. coli outbreak in Germany, some Canadian farmers are worried the crisis could hurt their businesses as concern over the safety of produce increases.

The European outbreak was initially attributed to Spanish cucumbers but officials later ruled them out. Suspicion was then cast on sprouts from Germany, but authorities backtracked again Monday, though they stopped short of giving sprouts a clean bill of health.

The outbreak has killed 22 people and sickened more than 2,300 across Europe. An Ontario man who visited Germany and consumed local produce has Canada's first suspected case of E. coli linked to the outbreak overseas.

George Gilvesy of Ontario Greenhouse Vegetable Growers, an organization that represents 224 members who grow tomatoes, cucumbers and bell peppers, says a serious scare like the one in Germany is bound to make some people think twice before putting certain items in their shopping cart.

"Because of this kind of news, the comfort of the shopper who would go to the store and just pick these things up on a regular basis, it puts some thought into their mind of should they or shouldn't they," he said.

Gilvesy says he has noticed a slight dip in demand for some items on the east coast of North America.

"We are seeing some impact because obviously people have been getting a fair bit of news on this," he said.

Mississauga, Ont.-based Sprout King Corp., tests its sprouts monthly for E. coli and salmonella, said plant manager Vina Quyen. Sales haven't fallen since the European outbreak was first detected in late May, but every time there's a story about tainted sprouts, his business suffers so he's concerned.

"Of course we're worried about it," said Quyen.

Independent grocery stores haven't reported a drop in vegetables sales, but shoppers have made in-store inquiries about where produce is coming from and whether it's safe, said a spokesman for the Canadian Federation of Independent Grocers.

"Those things happen from time to time around the country," said federation president John Scott. "We've seen that before on this continent as well. People back off certain products for a certain period of time but usually in the localized market area."

The Canadian Food Inspection Agency has increased sampling and testing of cucumbers, lettuce and tomatoes from the European Union. There is no indication any contaminated product has been shipped to Canada, it said.

Gilvesy says his organization has also received inquiries from the public about what Canadian farmers are doing to ensure food safety. He says Canadian growers are required to meet strict food safety requirements and consumers shouldn't be worried.

But Prof. Rick Holley, a food microbiologist at the University of Manitoba, doesn't believe Canada is any safer than Europe because farming practices are similar. More should be done to separate animal agriculture from plant production, he said.

The housing boom has created a shortage of farming land so animal and plant operations, which are becoming larger and more intense, end up being consolidated, he said.

"So there's opportunity for movement of organisms from the animals... salmonella and E. coli... to produce," said Holley.

In the 1970s and '80s, one or two per cent of food-borne illness outbreaks were caused by produce but now it's up to 15 to 24 per cent, he said.

With the cause of the outbreak still a mystery, German authorities are warning against eating tomatoes, cucumbers, lettuce and sprouts, after European patients reported eating those vegetables before becoming ill.

Gilvesy says he's particularly concerned that scientists are having so much difficulty determining the cause of the outbreak of the particularly nasty strain of E. coli that has led to kidney problems in more than 600 people.

Tom Demma, general manager of the B.C. Vegetable Marketing Commission, said he hasn't heard of any drop in demand on the West Coast, but noted that demand for greenhouse vegetables can vary from week to week.