This electron microscope image made available by the Centers for Disease Control and Prevention shows a Listeria monocytogenes bacterium, responsible for the foodborne illness listeriosis. Elizabeth White/CDC via AP
At least some of the listeria cases appearing across 13 states in recent weeks came from prepared meals sold at Kroger and Walmart, federal health officials said on June 18.
The listeria outbreak has resulted so far in 17 cases, including three deaths.
