The CDC says 64 people have been infected with a strain of Salmonella since June 21, and 20 people have been hospitalized. However, public health officials believe the number of people sickened is likely much higher. They now believe raw oysters are to blame.

A voluntary recall has been issued for oysters distributed to restaurants and retailers in a handful of states, including Florida, due to the possible presence of salmonella and E. coli, according to the FDA.

A shellfish harvesting area in Florida has been closed.