Dole Food Company, Inc. is being investigated by the U.S Department of Justice (DOJ) concerning a deadly Listeria outbreak in Canada and the United States.

The DOJ contacted the company regarding the outbreak, The Wall Street Journal and other media reported last week.

Westlake Village, California-based Dole said it would cooperate with the DOJ, which declined to comment to the Journal on the probe.

The multistate outbreak of Listeria monocytogenes (listeriosis) was traced to packaged salads produced at Dole’s processing facility in Springfield, Ohio. Nineteen people in nine states were infected and one person from Michigan died from listeriosis. The same outbreak was linked to illnesses in Canada, where 14 people fell ill and three died. On Jan. 27, Dole voluntarily recalled all salad mixes produced in the Springfield, Ohio processing facility.

Dole revealed the probe after Food Safety News reported that the company found positive results for Listeria contamination at its facility several times in 2014 and 2015, but continued to produce salads there. In July 2014, Dole performed swab tests of surfaces in the Springfield plant, which revealed positive results for Listeria, and Dole’s internal tests showed Listeria contamination at least five more times in 2014 and three times in late 2015, the article said, citing FDA inspection reports that were obtained through a Freedom of Information Act request.

Dole, whose roots track back to the 1800s, said it has “corrected" issues raised in the FDA observation reports. “We have been working in collaboration with the FDA and other authorities to implement ongoing improved testing, sanitation and procedure enhancements, which have resulted in the recent reopening of our Springfield salad plant," the company said in an April 29 statement.

The DOJ has investigated and prosecuted a number of companies in recent years in response to outbreaks of foodborne illness.