WASHINGTON — The US Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) detected viral particles in a cull dairy cow on May 22 as part of its most recent H5N1 study.

Out of a sample of 96 cows condemned at federally inspected facilities, only one was found with viral particles in tissue samples, including muscle, FSIS said.

“FSIS personnel identified signs of illness in the positive animal during post-mortem inspection and prevented the animal from entering the food supply,” the agency reported. “This type of inspection is part of routine FSIS operations. These actions provide further confidence that the food safety system we have in place is working.”

As part of the study, FSIS collected multiple tissues from muscles and the diaphragm of cows condemned for systematic diseases. The samples were analyzed by USDA’s Animal and Plant Health Inspection Service (APHIS) using PCR testing.

PCR testing does not differentiate between live virus or fragments, the agency noted.

Currently, FSIS and APHIS are working together on traceback activities, including notifying the producer to gain further information.

As more testing is completed, FSIS said it will provide updates to the public.

USDA has confirmed cases of highly pathogenic avian influenza (HPAI) in dairy milking cattle in nine states: Colorado, Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota and Texas.

The Centers for Disease Control and Prevention (CDC) on May 22 reported a human case of HPAI in Michigan.

Health officials with the US government developed two vaccine options, which are in the country’s stockpile.