The Centers for Disease Control and Prevention is investigating illnesses in 26 people across 15 states, thought to have been caused by cucumbers tainted with salmonella.

U.S. health officials are investigating a new outbreak of salmonella illnesses tied to a Florida grower whose tainted cucumbers were linked to more than 550 illnesses last year.

"Children younger than five, the elderly, and people with weakened immune systems are more likely to have severe infections," the FDA said.