The Centers for Disease Control and Prevention said Friday that a recent outbreak of E. coli in multiple states was linked to romaine lettuce grown in Yuma, Arizona.

“Information collected to date indicates that chopped romaine lettuce from the Yuma, Arizona growing region could be contaminated with E. coli O157:H7 and could make people sick,” the CDC said in an update on Friday.

The CDC said that no brand, distributor or supplier has been identified in connection with the E. coli outbreak. But it said that anyone who has bought romaine lettuce or salad mixes that contain romaine lettuce should throw it away, and ask restaurants if the romaine lettuce is from the Yuma region. The CDC also advised restaurants against selling any romaine lettuce from Yuma.

The CDC said Thursday that it was investigating an E. coli outbreak across at least seven states; that number increased Friday to 11 states. The outbreak has infected 35 people, 22 of whom have been hospitalized. Three have developed hemolytic uremic syndrome, a form of kidney failure.