What is the primary method of contracting listeriosis?

Listeriosis is primarily contracted through the consumption of contaminated food, particularly foods that are raw or have been improperly handled. The bacteria Listeria monocytogenes, which causes listeriosis, is commonly found in certain foods such as unpasteurized dairy products, processed meats, and ready-to-eat meals that have been contaminated. People can become infected when they ingest food that has been contaminated with the bacteria, often during the preparation, processing, or storage stages.

While drinking unpasteurized milk can certainly be a method of contracting listeriosis and is specifically associated with the bacterium, the broader category of eating contaminated food encompasses a wider range of potential sources for infection, making it the primary method of contracting listeriosis.