Bird flu has been detected in a sample of raw milk sold in California raising fears about the continued spread of the virus, state officials reported.

The virus was found in “one batch of cream top, whole raw milk” from Raw Farm, a dairy farm based out of Fresno, California, with a “best by” date of 27 November, said the California department of public health in a press release.

While no illnesses have been traced to the batch, the state’s health department is warning consumers to avoid purchasing the milk.

California officials have regularly been testing raw milk samples as a response to the flu. The discovered sample was tested by the Santa Clara county public health laboratory.

Health officials have long warned against the consumption of raw milk, as interest in the beverage rises. Unlike pasteurized milk, which is heated to kill bacteria, raw milk carries a higher risk of food-borne pathogens.

The latest update on the H5N1 virus comes days after a California child was diagnosed with bird flu, the first reported instance with a US minor.

So far, there have been 35 US cases of bird flu, with 29 infections in California. The virus has been spreading largely among poultry and wild birds. At least 280 million birds worldwide have died due to the virus since 2021.

The virus spread to US dairy cattle in March, and most of the infected cattle were in California. Of the 616 herds infected, 402 herds were discovered in the state. US dairy workers have also been infected with the flu. Eight out of 115 dairy workers who interacted with infected dairy cows contracted bird flu, a rate higher than recorded cases.

If contracted, bird flu can cause a variety of symptoms including headache, eye irritation, fever and chills. Bird flu can be fatal to humans in severe cases.