Salmonella, listeria, E. coli: what you need to know about these toxic and sometimes deadly bacteria

  • Salmonella, main risk

Salmonellosis, of which several dozen cases have been detected in Europe with a possible link to Kinder chocolates, is the leading cause of death from food poisoning.

The editorial staff advises you

This disease, the cause of several hundred deaths each year in France, is caused by salmonella, a large family of bacteria also behind typhoid fever. Named after the American veterinarian who discovered them, Daniel Elmer Salmon, these bacteria mostly come from the digestive tract of animals.

A wide variety of foods, eaten raw, undercooked or contaminated after cooking, can be the source of contamination: meat, eggs or raw milk…

More rarely, contamination can result from the consumption of fruits or vegetables. It can also come from powdered milk. Symptoms of salmonellosis appear on average after one to three days of incubation. They are most often those of a gastroenteritis sometimes acute: diarrhea and abdominal cramps, slight fever, even vomiting.

But the infection can, in certain cases, be dangerous, even fatal: the smallest or the elderly can indeed find themselves in severe dehydration under the effect of diarrhoea. From complications are also possible, such as sepsis or meningitis. For severe forms, antibiotic treatment is indicated.

  • Listeria, second danger

After salmonellosis, listeriosis is the second cause of death by food poisoning with, in France, a few dozen deaths per year. It is caused by the bacterium Listeria Monocytogenes, recently found in several cheeses produced by a subsidiary of the Lactalis group, although no cases of infection have been reported.

The editorial staff advises you

In its so-called form “invasive”, listeriosis is particularly deadly: around a quarter of patients die from it, for example because of neurological complications like meningitis. Incubation usually lasts one or two weeks, but can last almost three months, and pregnant women are particularly at riskwith twenty times more risk of developing this infection than the rest of the population.

Like salmonellosis, listeriosis is treated with antibiotics. And like salmonella, listeria is eliminated by cooking and is therefore found in raw or undercooked foods : meats, dairy products, vegetables and fresh fruits… But it also has its specificities. While the cold slows the development of salmonella, this is not the case for listeria which can reproduce in large numbers in a refrigerator.

Listeriosis is therefore often linked to “foods that can be kept for a long time in refrigerated conditions”summarizes the World Health Organization (WHO).

  • E. coli, difficult to treat –

Highlighted in the news by a recent outbreak of cases in France, linked to Buitoni pizzas (Nestlé), Escherichia Coli is the cause of significantly fewer deaths than salmonella and listeria.

The editorial staff advises you

This is a large family of bacteria, many of which are present in the human digestive system and even help it function. But some varieties can cause intoxications. Again heat kills them and these are a whole range ofraw or undercooked foods which can be incriminated, from certain meats to sprouted seeds, as in the worst epidemic observed to date in Europe in 2011.

In rare cases, these poisonings, which appear three to four days after ingestion, can degenerate into “hemolytic uremic syndrome” (SHU), with in particular a renal failure. Like salmonellosis, it is especially the elderly and children who are at risk. But, unlike salmonellosis and listeriosis, antibiotics should not be used, which may on the contrary make things worse. Severe E. Coli infection is therefore particularly difficult to treat.

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