Listeriosis is a serious foodborne infection caused by the bacteria Listeria monocytogenes. It causes sepsis or infection of the central nervous system. In pregnant women, it can cause abortion, premature labor, or severe neonatal infection.
What consequences can food poisoning caused by Listeria monocytogenes?
Listeria can cause listeriosis, a serious but rare disease that in some cases can lead to brain infection and even death. The elderly, newborns, pregnant women, and people with weakened immune systems are more likely to get listeriosis.
The infectious agent responsible for listeriosis is the bacteria Listeria monocytogenes. Due to its ubiquitous nature (presence in water, soil, plants) and its physicochemical characteristics, this bacterium has the ability to colonize food manufacturing sites. As a result, it is the cause of foodborne infections, epidemics in the event of the wide distribution of contaminated food.
Symptoms and treatment
The clinical signs of infection:
In adults, the disease results in an infection of the blood (sepsis), or even of the central nervous system, which then manifests mainly as meningoencephalitis (that is to say an infection of the meninges and the brain) . The incubation period ranges from a few days to two months; it is longer in the maternal forms (1 month) than in the septicaemic or neurological forms (a few days).
In pregnant women, the infection is usually harmless to the mother: it may go unnoticed, take the form of contractions, or rarely reduce to a feverish peak. On the other hand, the infected newborn presents a severe infection, often aggravated by prematurity, which can combine sepsis, pulmonary, neurological and sometimes skin infection. There is antibiotic treatment, the more effective the more quickly it is given. However, the course can be fatal even with appropriate and early treatment.
Treatment of listeriosis
Treatment of Listeria infection involves antibiotics; it is all the more effective when it is administered early.
In the current state of knowledge, there is no evidence in favor of the systematic implementation of antibiotic prophylaxis (treatment with antibiotics after exposure to a risk of contamination by Listeria) in the absence of a suggestive clinical sign. listeriosis in a person who has consumed a contaminated product.
The bacterium Listeria monocytogenes was described for the first time in the 1920s, but it was not until the discovery of a food origin of the infection in humans, during an epidemic in Canada in 1981, that listeriosis is considered a real public health problem. In France, it has been a notifiable disease since 1998.
Listeriosis occurs as sporadic cases, to which may be added clustered cases and even epidemics.
The most common mode of infection in humans is by ingestion of food contaminated with Listeria monocytogenes. The bacteria are sensitive to heat, but can still multiply at 4 ° C (refrigerator temperature). Contamination of food by Listeria monocytogenes is therefore encouraged by the extension of the cold chain (industrial cold stores, household refrigerators). Listeria monocytogenes does not alter the taste of food, unlike most other foodborne pathogens, explaining the possible repeated ingestion and in large quantities of this bacteria.
The foods most frequently contaminated by Listeria monocytogenes are cooked meats (tongue, head, rillettes), meat products, chilled sprouted seeds, fresh milk products (soft cheeses and raw milk) and processed foods.
Prevention and how to reduce the risk of infection with listeriosis?
Foods should be stored at temperatures above or below the dangerous temperature zone (i.e. 4 ° C to 60 ° C or 40 ° F to 140 ° F). Set the refrigerator temperature to 4 ° C (40 ° F) or less. Foods should be refrigerated quickly.
Cook raw meats well, such as beef, lamb, pork or poultry.
Wash raw vegetables and fruits before consumption.
Avoid unpasteurized (raw) milk or foods made from unpasteurized (raw) milk.
Isolate raw meat from vegetables, cooked foods and ready-to-eat foods, which may include using different cutting boards for raw meat and ready-to-eat foods.
Wash hands before and after preparing food and after handling animals.
Clean all utensils, cutting boards and work surfaces with lightly bleached water.
Look for “best before” or expiration dates on foods.
If possible, don’t buy more food than you need for a day or two.
In addition to the previous recommendations, here is a guide to reducing the risk of Listeria bacteria for those at greatest risk such as pregnant women, the elderly, and those with weakened immune systems.