The bacteria Listeria monocytogenes can cause the food-borne illness listeriosis, estimated to affect about 1600 people and kill 260 people each year in the U.S. Those at highest risk include pregnant people, newborns, people with weakened immune systems and adults age 65 and older. Listeria is particularly resilient and can appear in many foods, including cheese, lunch meats, ice cream, fruits, vegetables, and dairy foods.
Foods with higher likelihood of listeria include raw sprouts, melons, deli salads, dairy, fruit, unheated deli meats and unpasteurized cheese.The CDC has a helpful FAQ with infographics about listeria and maintains an ongoing, regularly updated list of listeria outbreaks since 2011. The agency also has an informative video and day-by-day breakdown of how epidemiologists identify listeria outbreaks and track down their source.