Milk sold in Canadian grocery stores tested for avian influenza; results released

Avian flu outbreak in U.S. dairy cattle Infectious disease specialist Dr. Isaac Bogoch says there are currently no active cases in Canada but people should still remain cautious.

As avian flu spreads south of the border, Canadian officials are now testing samples of milk sold in grocery stores across the country.

Results of these tests were made public Thursday, the day after a second U.S. dairy worker tested positive for bird flu, also known as H5N1.

The Canadian Food Inspection Agency (CFIA) said that all 303 samples of retail milk collected nationally as of May 16 tested negative for highly pathogenic avian influenza (HPAI) fragments. The milk samples showed no evidence of disease in dairy cattle, it added.

Despite some unpasteurized U.S. milk samples testing positive, Canadian health officials say there is no concern about the safety of the commercial milk supply because of the pasteurization process.

Why Canadian milk is safe

"Commercially sold milk and milk products remain safe to consume," the CFIA said in an update on its website. "The pasteurization process kills harmful bacteria and viruses, including HPAI, ensuring milk and milk products are safe to drink and eat."

It said pasteurization still retains the nutritional properties of milk.

Milk must be pasteurized before it is sold in Canada and all suspected cases of HPAI must be reported to the CFIA, it added.

"Highly pathogenic avian influenza (HPAI) has not been detected in dairy cattle or other livestock in Canada," it wrote. "HPAI is not a food safety concern and the risk of transmission to humans remains low."

How milk was tested

The CFIA said it tested commercial milk samples from across Canada using a type of polymerase chain reaction test. This method to test milk for HPAI is "very sensitive," allowing it to detect fragments of the virus even if it is not infectious, it explained.

The following is the number of samples assessed during testing completed on May 16:

What's next

Although there are no confirmed cases, the CFIA says it is continuing to monitor the situation and take proactive measures by testing commercial milk. It will also provide updates and consider any additional measures if necessary. "Our role in HPAI in cattle is to provide scientific guidance and diagnostic assistance and to report internationally," it wrote.

It said there are no impacts to trade of live cattle or their products. Canada requires imported lactating dairy cattle from the U.S. to test negative for HPAI as of April 29.

The CFIA says import controls are in place for cattle, including import permits, export certification and veterinary inspection.