(CNN) -- A frozen fruit mix commonly used in smoothies is suspected in a hepatitis A outbreak that has affected five Western states, according to the U.S. Centers for Disease Control and Prevention.
Thirty people have been infected with acute hepatitis A, and nine of them have been hospitalized. Infections have been reported in Arizona, California, Colorado, Nevada and New Mexico, the CDC website said Friday.
Eleven of 17 ill people interviewed reported eating Townsend Farms Organic Antioxidant Blend, a mix of frozen berries and pomegranate seeds.
Company records show that the fruit mix with contaminated ingredients was sent to only Costco stores, said William E. Gaar, an attorney for Townsend Farms. Costco has removed the product from its shelves, he said.
The outbreak has been traced to a type of pomegranate seeds from Turkey that are in the Townsend Farms fruit mix, Gaar said. The mix contains pomegranate seeds and other produce from Argentina, Chile and the United States, according to the label.
"There is no indication that cherries and other berries are contaminated," Gaar said.
State health departments, the Food and Drug Administration and the CDC continue to investigate. The company was notified about the outbreak Thursday by the CDC, which sent investigators to the Townsend Farms processing plant in Fairview, Oregon, Gaar said.
Hepatitis A is usually transmitted via contaminated food or water, or by someone who's infected, according to the Mayo Clinic website. Frequent hand-washing is recommended to limit the spread of hepatitis A.
The highly contagious infection inflames the liver and limits its ability to function.
"Mild cases of hepatitis A don't require treatment, and most people who are infected recover completely with no permanent liver damage," the Mayo Clinic website says.
Severe cases can lead to liver failure and death, according to the World Health Organization.
There are an estimated 1.4 million cases of hepatitis A annually worldwide, according to WHO.
CNN's Greg Morrison contributed to this report.