The latest campaign against genetically modified foods took place in Canada on Tuesday when consumer groups, scientists and farmers joined forces to demand the federal government postpone approval of genetically modified wheat, saying the engineered crop could devastate wheat exports and harm human health. "This is an inadequately tested experiment that has no place contaminating our farms and food," Holly Penfound, a member of Greenpeace Canada, told a news conference. "Our government should be calling the shots, not the big biotech companies pushing GM wheat into the market," said Penfound who is Greenpeace's environmental health coordinator. The coalition of environmental groups, consumer watchdogs, and grain marketers sent a letter to Prime Minister Jean Chretien, asking him to put the brakes on introducing transgenic wheat until its effects on the environment, consumer health and agricultural trade are addressed. The groups were reacting to plans by U.S.-based biotech company Monsanto Co. to introduce the world's first genetically modified (GM) wheat, known as "Roundup Ready," a herbicide-tolerant spring wheat variety, between 2003 and 2005. Critics say that GM crops could cross-pollinate and pollute non-GM fields. "This is just really very powerful technology and it's got a lot of potential, but it's misapplied in this case. It's not something farmers want," said Bill Toews, a grain farmer in Kane, Manitoba. At a time when many of Canada's wheat customers in Europe and Asia are demanding GM-free certification, the Canadian grain industry is especially nervous about the ability and cost of segregating GM and non-GM crops. Canada is one of the largest wheat producers and exporters in the world, shipping about 12 million tonnes worth between C$3 billion and C$5 billion annually. "The whole world is looking at this from fresh eyes and I think in Canada we also need to look at our variety registration system or the regulations we have in place right now for approval and think about the fact that it is new technology and we may need to make a change," said Patty Rosher, market development program manager with the Canadian Wheat Board.