The CDC said at least 100 cases of the bacterial infection have been reported in 20 states.
The outbreak has been traced to Rocky Ford brand cantaloupes grown at Jensen Farms in Granada, Colo. which issued a voluntary recall of the melons on Sept. 14.
So far, five deaths from Listeriosis have been reported in Colorado and New Mexico, two in Kansas and Texas and one each in Maryland, Missouri, Nebraska and Oklahoma, the CDC said.
The Listeriosis outbreak is the deadliest food-borne illness outbreak in the United States since 1998.
Health officials said the number of cases will continue to grow because the illness can take weeks to develop.
It primarily affects older adults, people with weakened immune systems and pregnant women.
Antibiotics are used to treat the infection.