Detection of Listeria spp. in Foods: Microbiological Safety Tests

What are the Hazards of Listeria spp. In Which Products Can It Be Found? Where are the contamination and growth environments?

Listeria spp. What is it?

Listeria is a genus of bacteria known for some of its species, notably Listeria monocytogenes. These bacteria are a major cause of foodborne illness, which can pose serious threats to human health. Listeriosis is a serious infectious disease caused by the listeria bacteria and most often affects the following risk groups

Elderly
Pregnant women
Newborn babies
People with a weak immune system

Listeria monocytogenes is a type of bacteria that can grow and multiply in food, so it can survive and reproduce even in particularly cold environments. This feature increases its importance in food production and storage.

Listeria is a disease caused by all food products produced under unhealthy and inappropriate conditions. The genus Listeria includes 6 species. The only Listeria species pathogenic to humans is Listeria monocytogenes. Listeria spp. are very common in nature. They can be found and grow in soil, water, milk, red and white meat, leaf tissues of some green leafy vegetables.

In particular, Listeria monocytogenes is one of the most important foodborne pathogens causing disease in humans and animals. Listeria monocytogenes has the ability to grow and multiply at refrigerator temperatures, and it is a major problem especially in ready-to-eat foods. It is known that Listeria monocytogenes can multiply at refrigerator temperatures and can survive for several months in humid environments and up to two years in salty and dry environments.

In the analysis of L. monocytogenes, a presence/absence test is performed on 25 g of sample. L. monocytogenes in foods should never be present in ready-to-eat foods for infants and special medical purposes. No more than 100 cfu/g of L. monocytogenes should be detected during the shelf life of prepared foods.

Risks of Listeria spp.

Listeriosis can be transmitted through food consumption and manifests as food poisoning.
Infection is usually associated with refrigerated foods.
The bacteriumListeria monocytogenes is resistant to factors such as temperature, pH and salinity and can reproduce rapidly under inappropriate storage conditions.
It can cause severe health problems such as fetal deaths, meningitis and sepsis forpregnant women, newborns and individuals with weakened immune systems.

Where to Search for Listeria spp. in Food?

Chilled and Prepared Foods: Dairy products, meat and meat products, frozen foods and ready meals are risky food groups for listeria.
Bakery Products: Baked products can be contaminated with Listeria spp. under appropriate storage conditions.
Fruits and Vegetables: Raw or poorly processed fruits and vegetables can be favorable environments for the growth of Listeria.
Seafood: Especially cold seafood offers ideal areas for Listeria bacteria to live and grow.

Nanolab Laboratories Group continues to provide services within the scope of Listeria spp. Search in Foods. We also provide services in Rope Spore Census in Foods.

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