The CDC investigates a multistate E. coli outbreak linked to raw cheddar cheese

At least 10 people across four states — California, Colorado, Texas and Utah — have been made ill from an E. coli outbreak linked to raw cheddar cheese from the brand Raw Farm, according to health officials.

The Centers for Disease Control and Prevention said Friday that at least four people have been hospitalized and one person has developed hemolytic uremic syndrome, which can cause kidney failure.

"The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses," the CDC said.

Raw Farm, based in Fresno, Calif., agreed to initiate a recall on a number of its cheddar cheese products, according to the Food and Drug Administration.

In a statement, Raw Farm president Aaron McAfee said none of their products have tested positive for E. coli and the voluntary recall was issued out of "an abundance of caution."

"Our retail partners have pulled the product that is subject to this Voluntary Recall and all product on the shelf as of today is legal for sale," he added.

The 10 cases emerged between Oct. 18 and Jan. 29. Four of them were from California; three from Colorado; two from Utah; and one from Texas, the CDC added.

Among the eight sick people who were interviewed by health authorities so far, six people reported having consumed Raw Farm's raw cheddar cheese purchased at Sprouts Farmers Markets or Bristol Farms.

The FDA said other retailers may also carry the Raw Farm branded cheese. The contamination involves both the original and jalapeño flavor cheddar cheese, as well as the block and shredded version, the agency added.

This is not the first time that raw cheddar cheese from Raw Farm was found contaminated. Last August, California ordered a statewide recall after salmonella bacteria was detected in a routine sample of the product. No illnesses were reported at the time.

Then, in October, milk and heavy cream produced by Raw Farm were subject to a California recall after the products were linked to people who were sick with a salmonella infection. In San Diego, at least 12 people reported ill, three of whom were hospitalized.

The FDA advises people to avoid eating, selling or serving the Raw Farm brand of raw cheddar cheese while the investigation is ongoing. Symptoms of an E. coli infection include nausea, stomach cramps, diarrhea or vomiting and they can appear up to nine days after eating the contaminated food.