Listeria, Salmonella .. These are dangerous bacteria to health that contaminate our food

A black streak of foods contaminated with various bacteria, potentially dangerous to health, has been affecting France for a few days, causing some concern among consumers.

Last week, Escherichia coli contamination has been linked to Buitoni’s brand pizza. This Monday, Ferrero Group recalled several batches of Kinder products suspected of being linked to cases of salmonellosis, and on Tuesday, it recalled cheese, potentially contaminated with listeria.

The accumulation of these ads within a few days is concerning because these infections, most of which are not serious, can have serious effects in some: two children who had serious cases of hemolytic uremic syndrome (HUS) and thus died after eating Buitoni’s pizza.

“It is estimated that 600 million people, or approximately 1 in 10 worldwide, fall ill each year after eating contaminated food, that 420,000 die as a result and that 33 million years of life are lost as a result of healthy lives,” WHO writes.

Salmonella, Campylobacter and Escherichia coli

The World Health Organization ranks these three bacteria “among the most common foodborne pathogens that infect millions of people every year with severe and even fatal consequences.” Campylobacter is thus “considered the most common bacterial cause of human gastroenteritis worldwide by the World Health Organization”.

The infection caused by these bacteria is usually mild, but it can lead to serious cases or even death of the infected person. Symptoms are often diarrhea (sometimes bloody) with abdominal pain, fever, headache (headache), and nausea or vomiting.

Humans generally get salmonellosis (a disease caused by salmonella) by eating contaminated food of animal origin such as eggs, meat or milk. Other food items can also transmit bacteria, such as vegetables that have not been washed well and that have been contaminated with manure.

For E. coli, “the food products in question are generally raw or undercooked meat, dairy products made from raw milk, and rarely raw plant products,” the Pasteur Institute writes, adding that “the faeces of ruminants found in the soil, in compost Natural. And in the waters (ponds and streams) a potential source of pollution.”

also for campylobacter bacteria, “The most common method of transmission appears to be eating undercooked meat and meat products, as well as raw, unpasteurized or contaminated milk,” says Health Canada. “Consumption of contaminated water or ice is also a known source of infection.”

To prevent the spread of this bacteria, it is important to follow strict hygiene measures throughout the food chain. In cases of severe diarrhea, fluids and electrolyte (mineral) supplements may be recommended. Antimicrobial therapy is also recommended for certain cases of Campylobacter or Salmonella infection, or even antibiotic therapy for the latter.

Yersinia coli

Less well-known, Yersinia infection “is the third cause of bacterial diarrhea in France and Europe, after Salmonella and Campylobacter,” the Pasteur Institute writes. In this family, Yersinia enterocolitica is most widespread in France.

Fecal-oral transmission: by eating “contaminated food: undercooked pork, raw vegetables or water”, but also “by direct contact with infected animals or people” and “contact with surface water, sludge or soil contaminated with residues Infected animals,” writes ANSES (National Agency for Food Safety).

Yersinia enterococcus “causes acute enteritis (inflammation of the intestine or stomach) accompanied by fever, diarrhea and abdominal pain, affecting all age groups, but with a predominance in children under 10 years of age,” the Pasteur Institute explains.

The disease remains “often mild” and resolves without treatment.


Human contamination with Listeria is primarily transmitted through food. These bacteria are “cold-resistant and therefore can multiply in the refrigerator and live in the refrigerator, but are killed by heat. Thus, raw foods are the most contaminated,” notes the USDA, which lists “unwashed fruits and vegetables, unpasteurized dairy products and milk cheeses.” raw, undercooked meat and charcuterie products, smoked and raw fish, raw shellfish or even sprouted seeds.”

It is possible for you to ingest the bacteria and be a healthy carrier, which means not to get a disease called listeriosis. It is a rare disease in France, “with about 5 to 6 cases per million inhabitants per year, or about 400 cases per year,” the ministry notes.

Listeriosis often results in “fairly high fever, accompanied by headache and sometimes gastrointestinal disturbances” such as nausea, diarrhea or even vomiting, according to the French Ministry of Health. Neurological complications (meningitis and encephalitis) can occur and threaten the vital warning of the affected person.

“Although the incidence of the disease is relatively low, the serious and sometimes fatal consequences, especially in infants, children and the elderly, are among the most serious foodborne infections,” asserts the World Health Organization, which speaks of “abortions in pregnant women or neonatal deaths.”

Prevention to avoid contracting this disease “is to avoid certain foods”, for example in pregnant women and newborns, for whom the disease can have serious consequences, “and in respecting special hygiene rules when preparing and preserving food”, the Ministry of Health defines.

Vibrio cholerae bacteria

If this disease, a true scourge of the nineteenth century, disappeared from France, the World Health Organization estimates that there would still be between 1.3 and 4 million cases of cholera every year in the world, resulting in 21,000 to 143,000 deaths. It is an acute diarrheal infection caused by ingestion of food or water contaminated with the bacillus. vibrio cholera, “One can die from it within a few hours in the absence of treatment.”

However, in the vast majority of cases, infected individuals do not develop symptoms, which does not prevent them from transmitting the bacteria. “Less than 20% of patients develop all the typical symptoms of cholera, with symptoms of moderate to severe dehydration: violent diarrhea profuse in ‘rice water’, vomiting, without fever,” Public Health France wrote.

These bacteria are now often transmitted in areas where access to safe drinking water is compromised. Thus, “high population concentrations, associated with defective environmental hygiene,” as for example in slums or overcrowded refugee camps “favor the emergence and development of cholera epidemics,” stresses the SPF.

Establishing good hygiene conditions (appropriate chlorination of water, hand washing, consumption of cooked and hot food) is essential to prevent the spread of cholera. Oral vaccines also exist, as well as treatment that consists in rehydrating the affected person, and allows recovery within a few days.

Salome Vincendon BFMTV journalist

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