Fishery products contaminated by harmful Listeria – Naturopathic and naturopathic specialists portal

Invisible health risk: listeria in fish

Listeriosis is a bacteria that can cause listeriosis. Transmission occurs primarily through the consumption of contaminated food. Fishery products are among the products that are particularly threatened. Therefore, they should be best avoided by certain risk groups.

Fish should be on the menu regularly as it is an important source of high quality, easily digestible protein, minerals and vitamins. But fishery products also often contain pathogenic germs such as listeria. (Image: photocrew /

Listeriosis is a rod-shaped bacteria that can cause listeriosis in humans. Infection usually occurs through food. The problem is, Listeria cannot be recognized in food because it does not affect the smell, taste or appearance. Foods particularly at risk include fish products.

Infection from contaminated food

According to experts, fish should be an integral part of the diet. It is an important source of high quality and easily digestible protein, vitamins and minerals.

But raw, smoked and pickled fishery products also often contain pathogenic germs, in particular listeria, reports the Federal Institute for Risk Assessment (BfR) in a current report.

Humans can become infected by consuming contaminated food and develop listeriosis. The Robert Koch Institute (RKI) received a total of 701 cases of severe invasive listeriosis in 2018, which translates to 0.8 cases per 100,000 population.

But not all listeria causes disease. According to the BfR, out of the 20 Listeria species described, only Listeria (L.) monocytogenes is important as a cause of infection in humans.

The disease can be fatal

According to information, most of the listeriosis diseases reported are serious and are associated, for example, with blood poisoning, meningitis or miscarriages. The disease was fatal in 5% of cases in 2018.

The elderly, people with weakened immune systems, pregnant women and their newborns are particularly at risk. Listeria can be found in a wide variety of foods of plant and animal origin.

Cold or hot smoked fish are often contaminated and are therefore also suspected of transmitting this disease. Other fish and seafood eaten raw, such as sushi, sashimi, and oysters, or pickled products such as cut fish may also be affected.

“Pregnant women, the elderly or those with weakened immune systems should only eat well-heated fish and marine animals,” advises Professor Dr. Dr. Andreas Hensel, President of the BfR.

As experts explain, Listeria can be reliably killed by heating food to 70 ° C in the heart for at least two minutes. However, at-risk groups should refrain from consuming raw, smoked and pickled fish and seafood products.

Danger for groups at risk

Listeriosis is generally not a threat to healthy adults, writes the BfR in a brochure. Most of the time, an infection has no symptoms and goes undetected. If symptoms do appear, they are quite nonspecific and flu-like. Fever and muscle pain may occur, as well as vomiting and diarrhea.

In the risk groups described, however, listeriosis can be associated with serious damage to health. Infections during pregnancy can lead to miscarriage, premature birth, stillbirth, or the birth of a sick child.

Additionally, listeriosis occurs mostly in people with weakened immune systems due to old age, previous illnesses, or medications. These people often suffer from blood poisoning, encephalitis or meningitis and, for example, inflammation of the inner lining of the heart or bacterial inflammation of the joints.

The BfR stresses that even low levels of germs pose a risk to at-risk groups if, for example, products are stored at home above the temperatures recommended by the manufacturer or are consumed after the expiration of their shelf life. . In addition, handling contaminated products carries the risk that Listeria could be transferred to other foods.

Listeria in many foods

L. Monocytogenes bacteria are not found only in fishery products. High detection rates can also be found in ground meat, raw meat preparations (eg tartare), raw sausages (eg onion sausage), and raw milk, for example.

Many other ready-to-eat foods of animal and plant origin which are not subjected to further germicidal treatment (eg heating) after processing may also contain L. monocytogenes.

These include cheese (made from raw milk or pasteurized milk), pre-cut salads and vegetables, cold cuts or cut sausages. This is because Listeria can survive for a long time in food manufacturing companies in niches that are difficult to access for cleaning and disinfection. According to the BfR, this can lead to continued infiltration of germs during food production. (a d)

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This text conforms to the requirements of specialized medical literature, medical directives and current studies and has been verified by health professionals.

Important note:
This article is provided for informational purposes only and should not be used for self-diagnosis or self-treatment. It cannot replace a visit to the doctor.