Federal officials say Canada is expanding its surveillance for a dangerous form of avian flu amid a growing outbreak of H5N1 in U.S. dairy cattle, with monitoring efforts now set to include testing of milk being sold on store shelves.

The Friday night update comes just days after leading Canadian researchers questioned the country’s response to the unprecedented spread of the virus among cows south of the border — including the discovery of viral fragments in processed milk.

“The Canadian Food Inspection Agency (CFIA), the Public Health Agency of Canada (PHAC) and Health Canada are monitoring this situation closely and would like to reassure Canadians that commercially sold milk and milk products remain safe to consume,” said the CFIA in its statement.

The CFIA had previously said that the agency was not testing any milk, but announced on Friday that Canada will now be “conducting enhanced testing of milk at the retail level” to look for any viral fragments that could signal cases appearing in dairy cattle here.

This form of avian flu is a reportable disease in Canada, the statement continued, which means anyone suspecting a case in animals, including poultry or livestock, must report it to the CFIA. Confirmed and probable human cases are also reportable to PHAC.

While Canada hasn’t had any human cases to date, tens of millions of birds have been infected by the virus, including poultry on various Canadian farms.

In its statement, the CFIA said Canada is also expanding its surveillance to manage the “possible emergence” of avian flu in cows by  requiring negative test results for lactating dairy cattle being imported from the United States to Canada and “facilitating the voluntary testing of cows” that aren’t presenting with any symptoms.

Speaking to CBC News in recent days, multiple Canadian scientists have also called for random testing of farm workers, wastewater surveillance and other proactive measures to try to catch potential H5N1 infections as quickly as possible.