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Listeria monocytogenes: The survivor amongst bacteria
New BfR leaflet provides information on protection against infections
A new consumer leaflet of the Federal Institute for Risk Assessment (BfR) provides information on protection against infections with Listeria. The leaflet is available from the BfR press office. As infections with these bacteria, particularly with Listeria monocytogenes, have increased in Germany and Europe in recent years, BfR felt it was necessary to inform consumers about this pathogen. With around 500 reported cases per year in Germany this infectious disease occurs comparatively rarely. Nonetheless, it is of major importance because of the severe course this disease takes. Infants, older people, pregnant women and individuals with a weakened immune system are particularly at risk. "Because Listeria can occur in foods, special attention to kitchen hygiene should be paid in the case of these groups", says Professor Dr. Dr. Andreas Hensel, BfR President. An infection with Listeria, also called listeriosis, manifests flu-like symptoms; in severe cases it may even lead to meningitis.
Listeria is ubiquitous in the environment and frequently reaches food during production, for instance during milking or slaughter. Inadequate hygiene during preparation may lead to contamination of food with this bacterium. Listeria monocytogenes is mainly found in raw foods of animal origin like minced beef and pork, raw sausage, unpasteurised milk and raw milk cheese and in certain fish products mainly smoked salmon and graved lax. Foods of plant origin like fresh vegetables or cut salads may also be contaminated with this bacterium.
Listeria is killed by heating, i.e. by boiling, roasting/frying or pasteurisation. By contrast, the bacterium is relatively insensitive to table salt and acid. It can also multiply at fridge temperatures or inside vacuum packaging.
Infants, older people, individuals suffering from diseases like cancer or diabetes mellitus, patients on immunosuppressive medication or pregnant women are particularly at risk from infection with Listeria. Pregnant women can pass on this infection to their unborn children. Healthy people do not normally become sick when infected with Listeria monocytogenes or merely develop minor symptoms.
Listeriosis manifests in flu-like symptoms like a high temperature, muscular pain, headache and limb pain. In individual cases it may start with gastrointestinal disorders. A severe course of the disease may lead to blood poisoning, encephalitis and meningitis and prove fatal. An infection with Listeria can be effectively treated with suitable antibiotics.
As Listeria may occur in food, BfR recommends on precautionary grounds that people with a weakened immune system, older individuals and pregnant women:
- do not eat any foods of animal origin raw.
- refrain from eating smoked or marinated fish products, particularly vacuum-packed smoked salmon and graved lax.
- do not eat any raw milk soft cheese and always remove the cheese rind.
- always prepare green salads themselves and do not use any cut packaged salads.
- use foods, in particular vacuum-packed foods, as soon as possible after purchase and well in advance of the ‘best before’ date.
Furthermore, by observing simple kitchen hygiene rules consumers can avoid the contamination of ready-to-eat foods with Listeria and prevent pathogen multiplication in the food.
The leaflet “Protection Against Food-Borne Infections with Listeria” is intended for consumers and multipliers. It is available in german language free of charge from the BfR press office (email@example.com or by fax on 030-8412-4970). It is also available on the Internet.