Alberta Health Services says 40 people in the province have become ill from eating raw oysters from British Columbia.
The outbreak, first reported in January, has caused 289 cases of gastrointestinal illness across the country.
The Alberta cases were reported in the Edmonton and Calgary regions, which include those cities and many nearby towns and rural areas. Some of the cases were confirmed to be norovirus.
Oyster bar looks to the East Coast
At a busy Calgary oyster bar, owner Heesung Kim says she is taking precautions to keep her customers safe.
At this time of year, she usually has 14 types of oysters for sale at Embarcadero Wine and Oyster Bar on 17th Avenue S.E. But right now she's only serving seven.
"It's a big issue with all of our West Coast supplies. Most of them are not shipping right now. So we're relying on East Coast, you know from Prince Edward Island and New Brunswick, to do our oyster feature."
The B.C. oysters she does serve come from a trusted supplier and are well cooked and on special, she said.
"All of these viruses are very, very easily killed by cooking, but obviously most people who love oysters like to eat them raw," she said.
Customer Ken Rogers says he doesn't think anyone at the restaurant was worried about getting sick.
"I don't think that scares a lot of people off from oysters. It's like an acquired taste. You like them, you'll eat them — and they'll find you ones that aren't contaminated," he said.
Properly cook shellfish, warn authorities
Health Canada is still investigating the outbreak linked to B.C. oysters and have not discovered the source.
Symptoms linked to contaminated raw oysters or shellfish include watery diarrhea and abdominal cramps. People can also experience nausea, vomiting, fever, headache and bloody stools.
To reduce the risk of illness, AHS advises the public to eat only properly cooked shellfish. Oysters specifically should be cooked to an internal temperature of 90 C for 90 seconds.
Mussels, oysters and scallops with shells that don't open after they are cooked should be thrown out.
AHS also recommends wearing gloves while handling shellfish, and to always keep them refrigerated.
People who develop symptoms within 10 to 50 hours after eating raw shellfish should contact the health link line at 811, AHS said.
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