Three new cases were linked to a listeriosis outbreak tied to Dole s production facility Thursday, according to information from the CDC. Stores across the region have pulled pre-packaged salads produced at the site from their shelves. JEFF GUERINI/STAFF HANDOUT

5 things to know about Dole listeria outbreak

In January, the Dole Food Co. in Springfield had to recall thousands of bags of pre-packaged salads and close its production facility after health officials linked the plant to a listeria outbreak.

Grocers everywhere that received the pre-packaged salad product raced to pull the products from their shelves.

But by then, multiple people in the U.S. and Canada had been affected.

The Springfield News-Sun is reporting that the U.S. Justice Department has launched a criminal probe into the Dole Food Co. over the outbreak, which is linked to a handful of deaths and even more illnesses.

Here are five things to know about Dole and the outbreak:

What is listeria?

Listeria is a food-borne bacteria that can be found in meats, some soft cheeses, and in raw vegetables. According to the CDC, the U.S. has about 1,600 illnesses and 260 deaths annually from listeria. Wikipedia reports that the first documented cases of Listeria was in 1924.

How many people were affected?

The Center for Disease Control and Prevention reports that the listeria outbreak affected the health of 19 people in the U.S. and 14 people in Canada. Out of the 19 affected in the U.S., one man in Michigan died. Three people in Canada died as well, though the Canadian Public Health Agency has said that it has not been determined if listeria contributed to the cause of those deaths.

Early warning signs

A government report showed that the company had evidence of the potentially dangerous bacteria in its Ohio salad plant almost a year before the recall, according to the Journal. The Dole plant in Springfield tested positive for the bacteria as early as July 2014. Federal inspectors also said the company failed to adequately test their plant for dangerous bugs.

Which products were recalled?

Several brands and varieties of salad mixes throughout the Eastern U.S. and Eastern Canada had products recalled. You could identify the potentially dangerous product by the letter “A” at the beginning of the manufacturing code on the packages. Any of the salad mixes remaining in people’s homes would have expired by now, according to the CDC.

What is Dole doing now?

After the initial recall, many workers returned to work just a few days after production at the facility had been stopped. Last week, company officials in Springfield said that limited production had restarted at the facility and there are plans to expand production in the coming weeks.