A listeria outbreak, which spanned multiple states, sickened 12 people and killed one, was traced to a Dole factory in Ohio that makes packaged salads. The affected states include Michigan, Indiana, Massachusetts, New York, New Jersey and Pennsylvania.

According to the U.S. Centers for Disease Control and Prevention (CDC), they have been receiving listeria reports since July 5, 2015. The investigation kicked off in September 2015, however the source of the outbreak remained unclear until this January. Test results linked the outbreak to packed salad produced by Dole's Springfield facility in Ohio.

Dole already notified CDC that they ceased all operations at the Springfield facility. The company is also pulling out all the packed salads produced at the said facility. The CDC said there is no current proof suggesting packed salads in other Dole facilities are contaminated or linked to the current listeria outbreak.

Dole Fresh Vegetables Inc. announced the product recall on their website. The packed salads are sold under several brand names such as Dole, Simple Truth, The Little Salad Bar, Fresh Selections, President's Choice and Marketside.

Products in question are identifiable with a product code that starts with the letter "A", which can be seen on the upper right-hand corner of the product package. Dole said that other products such as fresh vegetables and fruits and packed salads from their other facilities are not part of the current recall.

"Laboratory tests showed that the Listeria isolate from the packaged salad was highly related genetically to isolates from ill people. This packaged salad was produced at the Springfield, Ohio Dole processing facility," said the CDC.

The federal health agency said that the isolated listeria was found in a Dole brand Field Greens packed salad collected by the Ohio Department of Agriculture from a retail area as part of their routine product sampling.

The CDC advised that people, restaurants and retailers do not eat, serve and repack the products in question. Health officials are now investigating the actual food source of the listeria outbreak and looking for more people who might have been sickened by the said products.

CDC estimated that listeria accounts for 1,600 hospitalizations annually leading to 260 deaths. People with compromised immune systems are the most at risk, namely pregnant women, seniors and young children. Listeria can lead to miscarriages and even infect newborn babies.

Photo: Adrian Scottow | Flickr