Westlake Village-based Dole Foods is facing a criminal investigation from the U.S. Department of Justice over a listeria outbreak that killed four people.

The Wall Street Journal first reported the news April 29. In January, Dole Foods suspended production at its Springfield, Ohio, processing facility and removed products from 23 U.S. states and three Canadian provinces. The outbreak began in September, hospitalized 12 people and killed four people ranging in age from 3 to 83 years old.

Samples taken at the plant tested positive for listeria as early as July 2014, according to the Wall Street Journal’s report. Federal investigators said Dole did not test surfaces at the plant that contacted food. Also, Dole tested other areas in the plant before food production but prior to sanitation.

Listeria outbreaks can be particularly problematic for food producers. In the past, food processers have had to shut down plants entirely because it can be difficult to find the source of an outbreak and destroy the bacteria.

The Centers for Disease Control and Prevention says on its website listeria can cause fevers, muscle aches and diarrhea. Even with prompt treatment the bacteria can cause death in older patients and patients with other medical conditions.

On April 21, Dole slowly began scaling up production at the plant and said it will provide updates as the plant returns to normal operations.

In a news release April 29, Dole said the Justice Department contacted Dole and the company corrected the problems at the plant.

“Dole has recently been contacted by the Department of Justice in connection with its own investigation, and we will be similarly cooperating with the DOJ to answer questions and address any concerns,” the company said in a news release. “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.

“We understand that these recent news reports may raise questions among our consumers and customers. They should be assured, however, that we have worked in conjunction with the FDA to address those observations and ensure that Dole products are safe.”

• Contact Philip Joens at pjoens@pacbiztimes.com.