LOS ANGELES, Nov. 20 (Xinhua) -- A total of 31 infant botulism cases have been reported in 15 U.S. states as of Wednesday, amid a probe into a potential link with contaminated infant formula, an update from the U.S. Food and Drug Administration (FDA) said.

Epidemiologic and laboratory data show that ByHeart Whole Nutrition infant formula might be contaminated with Clostridium botulinum, which is causing infant illness in multiple regions of the country, the FDA said.

All 31 infants have been hospitalized, and no deaths have been reported to date. Of the infants with demographic information available, ages range from 16 to 200 days, and 11 are female.

The FDA said it has received reports that recalled formula is still being found on store shelves in several states, and it is working with state partners and retailers to ensure the recall is effectively implemented.

The agency also noted that recalled products were sold through online marketplaces and shipped to customers outside the United States. Consumers worldwide are urged not to use any ByHeart brand infant formula.

The FDA said its investigation to determine the source of contamination is ongoing.