What temperature will Listeria kill

During pregnancy - always heat fish because of the danger of listeria

15.12.2020

While contact with Listeria is widespread, Listeria infections are still very rarely diagnosed in Germany - but the numbers are increasing continuously.

Infections with listeria, so-called listeriosis, are notifiable. The bacteria are found in nature on plants and in the soil and in water, in the meat of animals and fish and, for example, in animal excrement. They are transmitted to humans via the environment during milking, slaughtering or contamination. Listeria in food usually does not cause serious illness in adults, but only occasionally a brief, violent gastrointestinal reaction and a slight fever. In pregnant women, however, they can get to the unborn baby through the placenta. If the baby is infected, it can lead to severe inflammation in the brain and other organs, as the immune system of the unborn child is not yet able to fight off germs. The child does not always survive this infection and the damage often remains.

The number one good news is this: since Listeria are widespread, almost all women have developed immunity before they become pregnant, so the body's own antibodies can prevent infection of the unborn baby.

And the good news number two: Listeria can reproduce even at refrigerator temperature. But they cannot take heat. Warming up to 70 degrees kills the germs in food.
A few days ago, the Federal Office for Consumer Protection and Food Safety (BVL) presented the overall results for 2019 on food contamination from animal sources (zoonosis monitoring). One of the focal points in the report concerned listeria, which occur more frequently than is generally known in fish, but also in milk and meat products and on ready-to-eat salads and fruit: every tenth food made from raw milk and even every third imported fish from an aquaculture - Tilapia and Pangasius in particular were mentioned in the monitoring - is contaminated with Listeria *. Listeria are unfortunately insensitive to smoking, salting and pickling: every sixth sample of cold-smoked or pickled fish ("gravlax") contains the disease-causing bacteria, according to the results of food monitoring in Germany from 2007 to 2017. It keeps coming back therefore after food controls to recall campaigns in the trade. Only heating or soaking in strong acetic acid can safely destroy the germs; Freezing only temporarily inhibits their growth, but does not kill them.

Freezing does not kill the germs either

While contact with Listeria is widespread, Listeria infections are still very rarely diagnosed in Germany; however, the numbers are increasing continuously. "A pregnant woman is only on the safe side if she completely refrains from eating fish and seafood that has not been heated during pregnancy and carefully avoids all other sources of infection," summarizes Dr. med. Christian Albring, President of the Professional Association of Gynecologists. “Most women know that they are not allowed to eat products made from raw milk or raw meat such as mett or salami, also because of the risk that they and the child could become infected with the dangerous toxoplasmosis.

Listeria infections from fish and other foods have received too little attention so far, even though they can seriously damage the unborn baby. On the other hand, fish is an important food source of iodine and omega fatty acids during pregnancy. However, it should always be thoroughly heated. ”Since the diagnosis is usually made late and treatment with antibiotics is not always carried out in good time, prevention is the most important measure to protect the unborn child from this dangerous infection.

* The germ Listeria monocytogenes is always meant here.

Further literature sources:
Information "Protection against food infections with Listeria" from the Federal Institute for Risk Assessment.
Information "Listeriosis and toxoplasmosis - Eating safely during pregnancy" from the aid information service.

Source: Health information from the professional association of gynecologists

Author (s): äin-red