SPRINGFIELD, Ohio — A Dole Fresh Vegetable Inc. plant in Springfield was shut temporarily, voluntarily by company officials last Thursday after one person died and 12 others were sickened from a listeria outbreak linked to packaged salads made at the Dole facility.

Those infected were in Indiana, Michigan, Pennsylvania, Massachusetts, New Jersey and New York. The U.S. Centers for Disease Control and Prevention (CDC) said the packaged salads made by Dole are the likely source of the outbreak. The salads are sold under several brands, including Dole, Fresh Selections, Simple Truth, Marketside, The Little Salad Bar and President’s Choice.

The salads can be identified by a product code that begins with an “A” on the packaging and were sold in 23 states as well as in Ontario, New Brunswick and Quebec in Canada. The CDC says customers should not eat food from those bags.

Several packaged salad products have been recalled, including Dole and store brands for Aldi, Meijer, Walmart and Kroger. The Cincinnati-based Kroger said Saturday it has removed products from sale in 10 states, including Ohio, Indiana and Kentucky. According to Erin Sykes, press officer with the CDC, a technology called molecular detection is relatively new to tracking listeria and helped trace the bacteria to the Dole plant.

“And this helps us to get a genetic fingerprint specific to the outbreak that’s causing the illness,” Sykes explained, “so we were able to identify this fingerprint among the people who got sick and in the Dole facility.”

Listeria is a foodborne bacterial illness typically found in raw vegetables and meats, as well as some soft cheeses. Vegetables can become contaminated from the soil or from manure used as fertilizer. Sykes said Monday she did not have information on how the salads became contaminated and how the bacteria spread.

Dole is a top 25 employer in Clark County and has had a local presence since 2007. It started a $9 million expansion in 2014 to add more than 130 jobs and retain about 600. The expansion included three new packaging lines and one processing line for spinach, spring mix and baby lettuce products.

Bill Goldfield, Dole Foods’ corporate communications director, could not be reached for comment Monday, but Keith Dailey, Kroger director of media relations and corporate communications, said that aside from Ohio, Indiana and Kentucky, stores under Kroger’s corporate umbrella in Michigan, Illinois, Tennessee, Arkansas, Mississippi, as well as portions of Missouri and Alabama, are affected.

Walmart spokesperson Scott Markley said the packaged salads have been pulled from their shelves and customers can return the products for a full refund.

The CDC and U.S. Food and Drug Administration have been investigating a multistate outbreak since September 2015, but the illnesses weren’t linked to the Springfield site until lab results from a packaged salad collected in Ohio traced the illness to there. No other Dole products, including fresh fruit, vegetables and salads packaged at other facilities, were included in the recall.

“State inspectors randomly test ready-to-eat products from grocery stores, including bagged salad, fresh produce, bottled water, juice or ice cream,” Ohio Department of Agriculture spokesperson Ashley McDonald said. “They look for bacteria, including salmonella, E. coli and listeria. If any of those get a positive, we’ll then notify the facility. That’s how this product came to get a positive test.”

The CDC estimated about 1,600 cases of listeriosis occur annually in the United States; about half of those are reported and, nationally, 93 cases were linked to a food source last year.