Fish imported from Vietnam and used commonly in Asian dishes have tested positive for a banned form of fungicide.
Malachite green, which some tests have shown to cause cancer, created serious consumer concerns in Hong Kong last summer when it was found in fish imported from China.
The fungicide is banned in imported fish, with zero tolerance for any sign of the industrial dye, used regularly until the early 1990s in hatcheries to treat fungal and parasitic infections on fish eggs, fish and shellfish and as a general disinfectant.
The Consumer Association of Canada is calling for the Canadian Food Inspection Agency to ban the import of farmed fish immediately as a result of the test findings.
"We're suggesting that until CFIA gets this sorted out in a way that will guarantee no MG gets into food sold here, that they ban it entirely," said Bruce Cran, president of the association. "Within hours of a minor outbreak of avian flu, our products were banned in the U.S. and other Asian countries."
Exposure to malachite green leads to temporary or non-life-threatening health consequences, according to Health Canada, and the probability of serious adverse consequences is considered remote.
Nonetheless, CFIA has increased its monitoring of imported aquaculture products from Vietnam and China after a small sample showed nearly 50 per cent contained malachite green.
CFIA began testing for the chemical in 2002, and since the end of September has tested all farmed fish from those countries.
Of the 1,500 lots of fish entering Canada since the beginning of the year, CFIA tested 138 samples and found 43 per cent contained malachite green.
"We take anything that is a potential health risk seriously," said Stephen Stephen, the national manager of technical standards in the fish, seafood and production division of the agency. "We've recognized that maybe we should be looking at it as much as possible. We believe we have a very strong control program, and we're addressing this issue properly."
Since the end of September, CFIA says it has inspected and tested 100 per cent of imported farmed fish and increased communication with authorities in Asia in an attempt to eliminate the problem.
Mr. Stephen said the agency would have put out an alert if Health Canada had informed the CFIA that MG poses a serious and immediate health risk. Because the fish is sometimes sold frozen, Mr. Stephen said, the CFIA is attempting to contact suppliers and sellers to advise of the potential risk.
CTV News tested nine samples of imported tilapia, eel and basa in a certified lab after purchasing the fish from supermarkets in Vancouver and Richmond.
Two samples of basa, which is similar to catfish and imported from Vietnam, tested positive for malachite green.
Environmentalist Bill Chu has been pushing CFIA to conduct more tests since August, when reports surfaced about the problem in imported fish in Hong Kong.
"My concern is that CFIA did not take this seriously because the consumers are Asians and perhaps they did not think that many people eat this type of fish," he said.
The imported fish are available through both Asian and non-Asian supermarkets and served in restaurants.
Ian Tostenson, president of the B.C. Restaurant and Foodservices Association, said yesterday that the public is learning about the potential problems and he is hopeful suppliers will address the problem.