The B.C. Centre for Disease Control is looking into the results of a CBC News investigation that found a potentially dangerous strain of Listeria bacteria in smoked salmon at a popular Vancouver market.

Dr. Tom Kosatsky, the director of Environmental Health Services, said inspectors are trying to determine where the smoked salmon nuggets were produced, where the contamination took place and whether a recall is necessary.

"Where positive samples occur, there is concern, and there is action that takes place," said Kosatsky.

CBC News bought the salmon nuggets at Longliner Seafoods on Granville Island. The manager there said they were smoked at a facility in Maple Ridge.

The Listeria bacteria was detected when CBC News bought a selection of deli meats and smoked salmon from nine stores around Vancouver and had them tested at a food microbiology lab at UBC.

On Tuesday, CBC revealed there was no Listeria on the meats, but two smoked salmon samples had strains of the bacteria, including one sample that had the toxic Listeria monocytogenes strain.

The bacteria was detected at a level low enough it wouldn't trigger a recall in Canada, but some countries, such as the U.S., have zero tolerance for any detectable levels of Listeria.

Contamination at 5 B.C. producers

The results of the CBC News investigation match the results of an unreleased study by the B.C. Centre for Disease Control that also found Listeria in smoked salmon from up to five producers in B.C.

Some salmon nuggets purchased in Vancouver in a CBC News investigation were found to contain Listeria bacteria. (CBC) The study looked at 293 samples of ready-to-eat foods — including meat, dairy and fish — purchased in B.C. between August and October 2009.

It found potentially toxic Listeria bacteria in 18 per cent of ready-to-eat fish products tested in B.C. All of the contaminated fish was smoked salmon, the study found. It also concluded fish processing facilities need more scrutiny.

The results triggered at least one recall in November 2009, of Smoked Salmon Cream Cheese Log and Maple Salmon Nuggets from Classic Smokehouse Inc.

However, the full results and recommendations have not been released. The B.C. CDC told CBC News it plans to release the report once the B.C. government is finished reviewing it.

But Kostatsky said that since the study was completed, some action has been taken to remedy the problems it found, including cleanup operations at the five processing facilities that were contaminated.

"The regional health authorities closed at least one plant in order to go through a full cleanup and insisted on cleanup of the other plants of which we're aware," he said.

Public should be informed

Kosatsky said the test results might lead to more regular inspection of fish processing facilities, but they should also be a reminder for people susceptible to listeriosis, including pregnant women and the elderly, to avoid eating smoked salmon.

Domenic Losito, the recently retired director of health protection for Vancouver Coastal Health, questions why the public wasn't immediately informed of the health risks.

"We have to be transparent with the public. We have to actually provide them with as much information as they can so they can make sound decisions," said Losito.

Experts say Listeria can grow on the food — even in the fridge — to levels that are dangerous to vulnerable people. The bacteria was blamed for 23 deaths in an outbreak traced to Maple Leaf deli meats two years ago.