The Canadian Food Inspection Agency (CFIA) has provided updates on its sampling and testing activities of retail milk for the presence of highly pathogenic avian influenza (HPAI) viral fragments, in response to the ongoing HPAI H5N1 outbreak affecting North American dairy cows. Additionally, Health Canada and CFIA recently completed a study that provides additional reassurance that pasteurization is effective in inactivating HPAI virus in milk.

As of June 18, 2024, a total of 600 retail milk samples have been collected from across Canada and tested in CFIA laboratories. This is double the number of samples that were tested at the time of CFIA’s last update in May. The samples were tested using a type of polymerase chain reaction (PCR) test that is highly sensitive and is able to detect fragments of the virus, even if the virus is not infectious. All of the 600 samples were negative for viral HPAI fragments.

With the oversight of Health Canada, in May–June 2024, CFIA laboratories carried out a study on the effectiveness of pasteurization to inactivate HPAI virus in milk. Consistent with similar studies published internationally, the results showed that pasteurization is effective. The pasteurization treatments tested were chosen to simulate those used by the Canadian dairy industry, and showed that they were effective at inactivating high concentrations of the virus that were added to raw milk.