Copyright The New York Times

Six people have died and at least 27 have become ill after eating prepared pasta meals that were contaminated with listeria and sold at major grocery chains across the country, federal health officials said. The meals, sold at Albertsons, Kroger, Sprouts Farmers Market, Trader Joe’s and other major stores, were recalled in recent months in connection with the outbreak, which the Centers for Disease Control and Prevention said grew last week. Federal health officials said the supplier, Nate’s Fine Foods Inc., had found Listeria monocytogenes, a bacterium that can cause illness and death, in a sample of its pasta. Health officials said that people in 18 states had been affected by the outbreak, and that they were working to investigate the source. Here’s what to know: The outbreak sickened 27 people in 18 states.