Liz Szabo

USA TODAY

A listeria outbreak linked to Dole packaged salads has hospitalized 12 people in six states in the past six months, including a Michigan resident who died of the illness, the Centers for Disease Control and Prevention reported Friday. In addition to Michigan, patients were from Indiana, New York, Pennsylvania, New Jersey and Massachusetts.

Tests from the Ohio Department of Agriculture found listeria bacteria in a package of Dole field greens produced at a processing facility in Springfield, Ohio. The bacteria was genetically related to the listeria found in people who became sick, according to the CDC.

In response, Dole shut down the Springfield facility. Dole is also withdrawing all packaged salads that were produced there, according to the CDC. The salads were sold under a variety of brand names, including Dole, Fresh Selections, Simple Truth, Marketside, The Little Salad Bar and President's Choice.

These packaged salads can be identified by the letter "A" at the beginning of the manufacturing code found on the package, the CDC said. People who bought these products should throw them away and wash the refrigerator drawer where they were stored, as well as any cutting boards where the greens were chopped.

There's no evidence to suggest that packaged salads produced at other Dole facilities are affected.

The outbreak began in July. Health officials did not isolated the cause of the outbreak until January, according to the CDC.

The listeria bacteria can cause a life-threatening illness called listeriosis. The condition causes fever and muscle aches, sometimes preceded by diarrhea or other gastrointestinal symptoms, according to the CDC. People with weakened immune systems, such as those being treated for cancer or AIDS, are at higher risk for becoming sick. Other people at high risk include newborns, pregnant women and the elderly, according to the CDC.

Rep. Rosa DeLauro, D-Conn., said the outbreak illustrates why the USA needs a better food safety system.

"Even though the investigation began last September, the source (of the outbreak) was not known until this month, leaving consumers across the country vulnerable to the outbreak," DeLauro said in a statement. "From the E.coli and norovirus outbreaks at Chipotle, to this latest incident with Dole, American consumers are being sickened, hospitalized and sometimes killed by deficiencies in our food safety system."