Boar’s Head has recalled more than 207,000 pounds of deli meat, including liverwurst and ham products sold nationwide, because they may contain the bacteria Listeria monocytogenes.

The company initiated the recall after liverwurst at a store in Maryland tested positive for listeria. The sample was collected as part of an investigation into a multistate listeria outbreak that had sickened 34 people across 13 states as of Thursday.

All but one of those people were hospitalized and two died: a patient in Illinois and another in New Jersey.

Health authorities say the outbreak is most likely linked to sliced meat sold at deli counters, as many of those affected reported eating items like turkey, liverwurst or ham.

The U.S. Department of Agriculture’s Food Safety and Inspection Service, which announced the recall Friday, said further testing is ongoing to determine if the Maryland sample is connected to the outbreak.

The recall includes Boar’s Head ready-to-eat liverwurst produced from June 11 to July 17 (view the product labels here), as well as other deli meat products that were manufactured on the same machinery around the same time, such as beef salami, bologna and ham.

A Board’s Head spokesperson said the company is conducting its own investigation and cooperating with government authorities.

“The health and safety of our customers is our top priority. As soon as a Listeria adulteration was confirmed in our Strassburger Brand Liverwurst, we immediately and voluntarily recalled the product,” the spokesperson said in a statement.

“Out of an abundance of caution, we also made the decision to voluntarily recall additional products that were produced on the same line and on the same day as the liverwurst product.”

People who bought the affected products should throw them away or return them to the store, and also clean out their refrigerators, the USDA said, since the bacteria can grow in cold temperatures and spread to other foods.

Listeria is the third-leading cause of death from food poisoning in the U.S.

Symptoms usually appear within two weeks of eating contaminated food, but they can sometimes develop right away or up to 10 weeks later. The initial signs include fever, muscle aches, tiredness, headache, stiff neck and confusion. In severe cases, the bacteria may cause a blood infection or meningitis.

The infection is most dangerous for people who are older or have weakened immune systems. Pregnant people with listeriosis can pass the infection to a developing fetus, increasing the risk of miscarriage, stillbirth or premature birth.

The Centers for Disease Control and Prevention advises those who are pregnant or otherwise vulnerable to avoid foods with a high risk of listeria contamination, such as deli meat, smoked seafood and soft cheeses made with unpasteurized milk.

Most healthy people who get infected don’t become seriously ill, however.

“For every one case that gets reported, there’s 15, 20, 25 cases that go unreported because there’s so many people who get sick and they go, ‘Oh, it’s a stomach bug, I’ll get over it,’” said Darin Detwiler, a professor of food regulatory policy at Northeastern University.

Sliced deli meat is considered high risk for a few reasons: For one, listeria that enters a manufacturing facility spreads easily among equipment and surfaces. Second, the meat is often stored in refrigerators and consumed cold, so there’s not enough heat to kill the bacteria.

Deli meat poses a lower risk if reheated until steaming hot or to an internal temperature of 165 degrees Fahrenheit, according to the CDC.

Detwiler said no company is immune to failures in food safety. In theory, he said, even “a small error when it comes to sanitation in a production facility can result in what we’re seeing play out right now.”

The CDC estimates that around 1,600 people get listeriosis each year, and about 260 die. Most cases aren’t linked to outbreaks, but there are usually a few outbreaks in a given year.

Earlier this year, the CDC identified a listeria outbreak linked to queso fresco and cotija cheese that led to 23 hospitalizations and two deaths.