Listeria monocytogenes causes human listeriosis. Listeriosis can exist in two forms: a self-limiting gastroenteritis and invasive listeriosis that can be life-threatening. The gastrointestinal form is characterized by flu-like symptoms (e.g., diarrhea, vomiting, and fever) that occur 9–48 hr after ingestion of contaminated food. In contrast, invasive listeriosis may have an onset time of 2–6 weeks, and adults may experience septicemia, meningitis, and endocarditis, whereas unborn fetuses may dev…