 you may want to toss out those cold cuts in your fridge over a deadly listeria outbreak linked to deli beet. Listeria is especially dangerous for anyone who might be pregnant, immunodeficient, or people older than 65. The foodborne illness can thrive in cold temperatures, so experts are urging you to stay away from deli items for the time being. Dr. Brian McDonough says contracting listeria while pregnant could result in a miscarriage. The symptoms of listeria are somewhat classic. You can have fever.