Federal regulators have added Iowa to the list of states where pre-cut melon tied to an outbreak of Salmonella infections that has sickened 60 people -- more than half of whom were hospitalized. 

The Centers for Disease Control and Prevention and the Food and Drug Administration are investigating the multi-state outbreak of Salmonella infections, first reported by the agencies on Friday, with fruit salad mixes containing pre-cut melons viewed as the likely source. 

Produced at a Caito Foods facility in Indianapolis, the fruit, packaged in clear plastic containers, was distributed to retailers in Georgia, Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, North Carolina and Ohio, the FDA said Tuesday in an update that upped the number of states to nine.

The suspected tainted fruit was sold at retailers Costco, Jay C Food Stores, Kroger, Owen's Market, Pay Less Super Markets, Sprouts, Trader Joe's, Walgreens, Walmart and Whole Foods/Amazon, according to the agency.

The strain of Salmonella Adelaide infecting people is proving to be more serious than many past outbreaks. Of the 60 people to become ill, the CDC had information on 47 cases, with 31, or 66 percent, involving hospitalization. No deaths have been reported. 

Caito Foods recalled the products shipped between April 17 and June 7. All had a "best used by" date of June 16.

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