The state Department of Health is investigating two cases of hepatitis A that may be linked to a frozen organic berry drink that was pulled from Costco shelves Wednesday.

DOH spokeswoman Janice Okubo said one case was reported on Oahu, the other on Kauai.

The Food and Drug Administration and the Centers for Disease Control and Prevention had previously linked 30 hepatitis A illnesses in five western states to Townsend Farms Organic Anti-Oxidant Blend, which is believed to contain a tainted pomegranate seed mix. Nine of the reported cases resulted in hospitalization, according to the CDC. The earliest illness report dates back to April 29.

Costco is contacting customers who bought the product since late February.

A Townsend Farms representative told The Associated Press that the company is checking to see whether any other retailer besides Costco may have distributed the drink.

According to the CDC, preliminary laboratory studies of specimens from two cases suggest the outbreak strain of hepatitis A virus is genotype 1B, a strain rarely seen in the Americas but known to circulate in North Africa and the Middle East.

This genotype was identified in a 2013 outbreak in Europe linked to frozen berries and another 2012 outbreak in British Columbia related to a frozen berry blend with pomegranate seeds from Egypt, the CDC said.