Tests have shown that Natural Balance pet food pulled from the market Tuesday was contaminated with melamine, a chemical used to make plastics and fertilizers, the U.S. Food and Drug Administration said.

The recall applies to the venison and brown rice canned and bagged dog food, venison and brown rice dog treats and venison and green pea dry cat food made by the California-based company.

The Canadian Food Inspection Agency will conduct a review to determine if the government should regulate the ingredients of pet food.
(CBC)

"We believe the source of the melamine is a rice protein concentrate," the FDA said in a release Tuesday. "Natural Balance has confirmed this morning that some production batches of these products may contain melamine."

Also Tuesday, Menu Foods expanded its recall to include a wider date range for selected products. The Ontario-based company also withdrew Natural Life vegetarian dog food sold in 13.2-ounce cans after tests showed the product to contain contaminated wheat gluten.

'We're trying to determine what, if anything, we can do to try to prevent these things from happening again.'—Chuck Strahl, agriculture minister

In March, Menu Foods recalled 60 million containers of its cuts and gravy style wet pet food, sold across North America under nearly 100 store and major brand labels. Since then, five other pet food companies have recalled products believed to be contaminated with wheat gluten containing melamine.

Meanwhile, Agriculture Minister Chuck Strahl has asked the Canadian Food Inspection Agency to conduct a review to determine if pet food should be regulated.

"What we are doing is reviewing the situation," Strahl said. "We're trying to determine what, if anything, we can do to try to prevent these things from happening again, and also what type of regulations might be effective on this kind of a product."

Under the current system, the Canadian Veterinary Medicine Association provides nutritional guidelines but has no regulatory powers. The NDP recently called on the federal government to tighten pet food production regulations.

The FDA traced the problem to melamine after pet owners grew concerned about apparent kidney failure in their cats and dogs. There have been 16 confirmed cases of animals dying in the U.S. after eating Menu Foods products.

With files from the Canadian Press