Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular opportunistic pathogen, which is ubiquitous to the environment. Listeria is often transmitted through contaminated food and causes a rare but serious disease called listeriosis. One fourth of the food poisoning-related deaths are caused by Listeria.
Several studies have found that Listeria enters the body through the intestines and can spread to the liver while eluding the immune system by entering hepatocytes and proliferating intracellularlly. Infected resident phagocytes often spread through the blood to the brain and uterus. Outbreaks of Listeria are often related to contaminated ready-to-eat (RTE) foods. The most recent outbreak dates from September 2008 in Canada. Fifty-two cases have been linked to Maple Leaf Foods, where 20 people have died from severe listeriosis. The company recalled 191 products, which has lead to millions dollars of damage. The food industry is constantly evolving to minimize the outbreaks. Recently, several companies have received governmental approval for the use of bacteriophage technology to ensure food safety.