Definition
"Listeria" generally refers to *Listeria monocytogenes*, a bacterium that causes listeriosis, a serious foodborne illness. It is a Gram-positive, rod-shaped bacterium able to grow even in refrigerated temperatures. Think of it as a cold-loving germ that can contaminate food. Listeriosis is especially risky for pregnant women, newborns, and individuals with weakened immune systems. Proper food handling and cooking are key to prevention. It is found in soil and water.