The U.S. Food and Drug Administration said this week that about one in five U.S. commercial milk samples from a nationwide survey contained traces of bird flu virus, but it maintained that the product remains safe to consume.

The public health risk posed by the H5N1 bird flu pathogen is minimal, the World Health Organization said Friday, adding that countries should remain vigilant and work to reduce exposure.

The FDA said late Thursday that additional testing was required to determine whether a live virus was still intact in the milk samples but added that there was currently no evidence that the milk posed a danger.

The U.S. Department of Agriculture and the FDA said that pasteurization used in production makes the milk safe for consumption, as it heats the milk to a specific temperature to kill harmful bacteria and viruses.

Further, milk from sick cows gets diverted or destroyed in the pasteurization process.

The FDA said in its latest update that “to date, the retail milk studies have shown no results that would change our assessment that the commercial milk supply is safe.”

However, the agency has warned against drinking raw milk, which has not undergone pasteurization and could pose health risks.

Thirty-three dairy herds in eight U.S. states have confirmed cases of the virus. Only one person in Texas has been confirmed to have contracted the virus, symptoms of which include conjunctivitis, or irritation of the eyes.

Beyond this one known case, there has been no uptick in cases, and the FDA will continue to assess findings.

While the testing confirmed the presence of viral bird flu fragments, embryonated egg viability studies, in which virus samples are injected into eggs, can clarify whether a virus can replicate.

The bird flu, despite posing minimal risk to humans, has negatively impacted the dairy industry in the United States. To minimize the spread of the virus, sick cows are required to be isolated from other cows and need supportive care to help them get through the illness.

Approximately 5% to 20% of animals in herds affected by the virus become ill. Affected dairy farms can experience economic losses and a temporary reduction in milk sales.

Some information for this report came from Reuters and The Associated Press.