Lab results found the same strain of listeria bacteria that has caused a listeriosis outbreak in four provinces in some meat products from the Toronto plant. Six people have died from the listeriosis outbreak. There have been 21 confirmed cases of the illness in Canada, with another 30 currently under investigation. Listeria was found in the systems of six other people who have died of other causes.

Dr. Colin Lee, the associate medical officers with the Simcoe Muskoka District Health Unit, said they still don't know the extent of the meat recall.

"There is a time delay for people infected. It's usually takes three weeks until people show symptoms, but it can be up to 70 days," he said. "If you ate it today, you won't know you have it for three weeks."

As a precaution, Maple Leaf Canada decided to voluntarily recall all meat products made at the Toronto plant, although no other meat products have tested positive since those named in the original recall on Aug. 17 and 19.

People are being warned not to serve or consume meat products that came from plant Maple Leaf plant 97B. All products from this factory will have the number 97B on the package, usually near the best before date or packaged on date.

The products can be returned to the point of purchase for a refund.

"The hard part is that food contaminated with listeria can look, smell and taste normal," Lee said. "When in doubt, throw it out."

Listeria can be found naturally in the environment in soil, sewage and feces. It can be found in unpasteurized dairy products and uncooked vegetables and meats. The food can also be contaminated after processing. The bacteria can be killed through proper cooking procedures.

Listeriosis symptoms can include vomiting, nausea, cramps, diarrhea, severe headache, constipation or persistent fever.

Lee said Simcoe Muskoka has had just nine cases of listeriosis in the past 10 years. There has been one reported case in 2008, which is still under investigation.

The recall not only affects Maple Leaf labelled products, but also some products from Compliments, Hickory Farms, Kirkland Signature, No Name, Schneiders and Shopsy's.

Restaurants affected include Boston Pizza, McDonalds, Mr. Sub, Pizza Nova and Tim Hortons.

For more information and a complete list of the recalled items, visit the Canadian Food Inspection Agency's website at www.inspection.gc.ca or call Maple Leaf Consumer Foods at 1-800-568-5801.