Listeria bacteria are non-spore-forming, gram positive, aerobic and facultative anaerobic bacteria. Listeria bacteria, which are eight different species in themselves, are common in nature and can live in the cold. It is therefore difficult to combat this type of bacteria.

Among the listeria species, listeria monocytogenes has the highest ability to cause disease. Bacteria of the Listeria monocytogenes species should not be present in food products in any way. On the basis of the directive containing microbiological criteria for foodstuffs, 2005 / 2073 issued by the European Union in 2005 was published by the Ministry of Food, Agriculture and Livestock in Turkey. This Communiqué mainly covers food products, dairy products, cereal-based products, sugary products, oils, processed vegetables and fruit products, soups, cocoa products, fermented products, mayonnaise and sauces, starch, bread yeast, black tea, filter coffee. discloses the microbiological criteria of salts, soft drinks, ready-to-eat daily meals and appetizers. The foodstuffs of the listeria monocytogenes bacterium species listed in the Communiqué should not be in any way in the 2009 gram sample.

Bacteria of the Listeria monocytogenes species are found in sewage waters, animal feeds, fertilizers, soil, plants and carriers (average percentage 10). It causes various infections in humans by switching to food.

Listeria bacteria are found in fresh and processed meat products, fresh frozen poultry meat, raw milk, soft cheeses and slaughterhouse waste. The way of transmitting to humans is to consume food contaminated with these bacteria. It can also pass from sick animals directly to humans.

In advanced laboratories, studies are carried out for the identification of bacteria of the listeria monocytogenes species within the scope of microbiological analyzes. During these studies, standards and test methods published by local and foreign organizations are taken as basis.