Listeria refers to a group of bacteria that can cause illnesses, including severe infections, particularly in the elderly, newborns, pregnant women, and individuals with compromised immune systems. The species Listeria monocytogenes is the most frequent cause of these infections. Symptoms of listeriosis can include fever, muscle aches, nausea, and diarrhea. If the infection reaches the nervous system, it may lead to headaches, a stiff neck, confusion, loss of balance, or seizures. During pregnancy, the infection might seem mild but can result in stillbirth, premature birth, or neonatal infection.There have been numerous food recalls due to Listeria contamination. The infection can spread through various means, such as direct contact with infected wounds, contaminated food, and from mother to child during pregnancy or delivery. To prevent infection, those at risk should avoid certain high-risk foods and practice safe food handling. This includes thoroughly cooking raw animal products like beef, pork, or poultry; keeping raw meats separate from vegetables, cooked, and ready-to-eat foods; washing raw vegetables well; and steering clear of unpasteurized milk or products made from it.The name Listeria honors Joseph Lister (1827–1912), an English surgeon and pioneer of antiseptic surgery. The illness caused by Listeria bacteria is known as listeriosis.