MONTGOMERY, Ala. (AP) — The Alabama Department of Agriculture and Industries is investigating three possible cases of avian influenza in the northern part of the state.

At a news conference Tuesday, Agriculture and Industries Commissioner John McMillan said the findings are in poultry in Jackson, Lauderdale and Madison counties. Dr. Tony Frazier, the state's veterinarian, also issued a stop-movement order for certain poultry in the state.

One of the avian flu investigations involves chickens at a commercial breeder in Lauderdale County, but significant deaths weren't reported. Another is a backyard flock in Madison County.

The most recent investigation began Sunday after USDA poultry technicians collected samples at the TaCo-Bet Trade Day flea market in Scottsboro in Jackson County.

McMillan told multiple media outlets that the cases are suspected and not confirmed. Samples from the sites have been collected and sent to the USDA Lab in Ames, Iowa.

"Our staff is committed to staying actively involved in the avian influenza situation until any threats are addressed," he said.

McMillan also said the suspected poultry cases are not a food safety issue. A department news release says none of the affected poultry made it into the food chain.

Under the stop-movement order, poultry owners and producers should refrain from moving birds to offsite locations or introducing new birds to their flocks, the department said in a news release.

The order, he said, "is the most effective way to implement biosecurity for all poultry in our state."

Alabama has been on alert since a 2015 outbreak in the Midwest. Last week, Tennessee officials confirmed a second commercial chicken-breeding operation had tested positive for the avian flu. That facility was in Giles County, south of Nashville and close to the Alabama state line.

Frazier has been working closely with the U.S. Department of Agriculture and the Tennessee Department of Agriculture and encourages commercial poultry producers and backyard flock owners to observe their birds closely and practice strict biosecurity measures such as isolating poultry from other animals, wearing clothes designated for use only at the poultry house and sanitizing the facility between flocks.

The Alabama Department of Agriculture and Industries Poultry Division should be notified at 334-240-6584 if birds show unusual signs of disease or flocks experience unexplained mortalities. The Alabama Cooperative Extension System has created a website to assist backyard flock owners and provide answers for Avian Influenza control. It can be found at www.AlabamaAvianInfluenza.com .