Federal regulators announced on Friday that producers of raw pet food for dogs and cats must improve their detection of bird flu in their products sold to consumers.

In the U.S., several cats—both wild and domestic—have contracted the H5N1 strain of avian influenza and have died after consuming raw food contaminated with the virus. Raw pet foods generally encompass unpasteurized milk, uncooked meat, and unpasteurized eggs. Despite health warnings and product recalls, the raw pet food sector has expanded quickly, as reported by YSL News.

Pasteurization is a commonly used heat treatment method that can deactivate viruses, including H5N1 and other harmful pathogens in food.

On Friday, the FDA announced that manufacturers of uncooked or unpasteurized dog and cat food must reassess their food safety plans to address bird flu as a potential threat. This update aims to make sure that pet food manufacturers understand the new H5N1 risk linked to their products, according to FDA officials.

There is a concern that pets infected with bird flu could potentially transmit it to humans. While human cases of bird flu have mostly been mild, there hasn’t been significant human-to-human transmission.

Studies suggest that cats, which can carry both bird flu and human flu viruses, might act as a mixing host. This could allow the bird flu virus to evolve in ways that increase its ability to infect humans, potentially leading to more severe illness.

Cats are particularly vulnerable to severe symptoms and death from bird flu. Recently, 20 wild cats died at an animal sanctuary in Washington due to raw food consumption. Additionally, domestic cats have died in California, Colorado, and Oregon after being given raw meat or milk products that were later recalled.

While dogs can also contract H5N1, no cases have been reported in the U.S. thus far.

According to FDA regulations, specific animal food manufacturers are obligated to implement a food safety plan that identifies and assesses hazards related to the foods they produce, process, package, or store.

The regulation mandates that manufacturers revisit their food safety plans whenever the FDA deems it necessary, as is the case now with the known transmission of bird flu through raw food products.

The FDA has urged pet food manufacturers and others in the supply chain to adopt practices that “significantly minimize or prevent” the transmission of bird flu through animal food—such as through pasteurization—and to source meat, milk, or eggs from healthy flocks or herds.