Listeria

Listeria is a family of bacteria that contains ten species A subdivision of the genus, a species is a group of closely related and similar-looking organisms; for example, in the case of Homo sapiens (humans), the second part of the name (sapiens) represents the species.. One of these, Listeria monocytogenes, causes the disease listeriosis.

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Although listeriosis is rare, the disease is often severe with high hospitalisation and mortality rates. In the EU about 2,400 infections were reported in 2017.

People usually become ill with listeriosis after eating contaminated food.

Cooking at temperatures higher than 65C kills the bacteria. However, Listeria can contaminate foods after production (for example contamination can occur after the food is cooked but before is packaged). Unlike many other foodborne bacteria, Listeria tolerates salty environments and can even multiply at cold temperatures (between +2C and 4C).

The hardiness of these bacteria, coupled with the high mortality rates in humans, means that safe handling of food is paramount to ensure public health.

In infected people, symptoms vary, ranging from mild flu-like symptoms, such as nausea, vomiting and diarrhoea to more serious infections such as meningitis and other potentially life-threatening complications. The disease primarily affects the elderly, pregnant women, new-borns and people with weak immune systems.

Listeria monocytogenes can be found in many foods. Examples include smoked fish; meats; cheeses (especially soft cheeses) and raw vegetables.

To prevent listeriosis, it is important to follow good manufacturing practices, hygiene practices and effective temperature control throughout the food production, distribution and storage chain, including in the home. Consumers should keep the temperature of their refrigerators low to limit potential growth of bacteria such as Listeria, which may be present in ready-to-eat foods.

International organisations such as the World Health Organization advise that foods should be refrigerated below 5C.

Latest

In 2022 listeriosis was the fifth most reported zoonosis in the EU, with 2,738 cases – a 15.9% increase in EU notification rate compared with 2021. It mainly affected people over the age of 64. See the latest annual EU One Health Zoonoses report by EFSA and ECDC.

EFSA has updated its interactive tools on Listeria monocytogenes – a story map and a dashboard. The story map provides general information on Listeria monocytogenes, its characteristics and distribution, as well as monitoring activities implemented in the EU. The dashboard allows users to search and query the large amount of Listeria monocytogenes data EFSA has collected from EU Member States and other reporting countries since 2017.

Milestones

2024
January
EFSA assesses the persistence of microbiological hazards in food and feed production and processing environments. EFSA’s experts highlight three harmful bacteria in food, Listeria monocytogenes, Salmonella enterica, and Cronobacter sakazakii and the potential threat they pose to public health due to their persistence Persistence refers to the ability of harmful organisms like bacteria to survive and thrive despite regular cleaning and disinfection efforts, potentially lingering in hidden places for months or even years. in food processing environments.
2020
April
EFSA assesses the risks to public health from Listeria contamination of vegetables that are blanched – scalded in hot water or steam for a short time – before they are frozen.
2018
June
EFSA provides scientific and technical assistance on sampling and testing strategies for the detection of L. monocytogenes in the processing plants of frozen vegetables.
January
Experts provide scientific advice on Listeria monocytogenesand risks to public health from consumption of contaminated ready-to-eat food. They conclude that between 2008 and 2015 Listeriacases increased among two groups of the population Community of humans, animals or plants from the same species.: people over 75 and women aged 25-44 (believed to be mainly pregnancy-related).
2013
June
The first part of EFSA’s analysis of an EU-wide baseline survey on Listeria monocytogenes provides insights into the presence of this bacterium in certain ready-to-eat foods (fish, cold meats and soft cheeses). The proportion of food samples exceeding the legal food safety limit was low. However, given the popularity of these foods and the severe implications that listeriosis can have on human health, overall vigilance regarding the presence of the bacteria in food is warranted.
2008
January
Scientists update their advice on the Listeria risks in foods. They recommend that efforts to reduce risks to human health should focus on risk reduction practices both during the production process of ready-to-eat foods (RTE) and at home by consumers.

EFSA's role

EFSA assesses food safety risks posed by Listeria for human health and advises policy makers on possible science-based control and mitigation options. It does so by:

Monitoring the presence of Listeria monocytogenes in the food chain annually in EU Member States.
Assessing the prevalence The proportion of a population found to have a condition. and levels of Listeria monocytogenes in certain ready-to-eat foods across the EU (such as soft cheeses, cold meats and fish) which may contain this bacteria.
Analysing the risk factors responsible for the presence and growth of Listeria monocytogenes in foods.

EU framework

The monitoring and control of foodborne diseases as well as food hygiene requirements and food safety criteria are regulated by EU legislation.

Commission Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs lays down food safety criteria for certain important foodborne bacteria, including Listeria monocytogenes.