Salmonellosis is a very common food-borne infection. Compliance with certain hygiene rules, especially when preparing, cooking and storing food, can prevent salmonellosis.

What is salmonellosis?

Salmonellosis is a very common food-borne infection, which is caused by the Salmonella bacteria. Salmonellabacteria mainly infect the digestive tract in humans and cause gastroenteritis.

Salmonellosis enters humans through the mouth, mainly whenfood from infected animals is eaten raw or is undercooked.

Salmonellosis is a benign disease and heals without treatment. However, you must drink enough water. Some frail and debilitated people can experience serious complications, such as septicemia or meningitis.

These infections are more common in the summer, when people host parties and barbecues, and foodstuffs are left at room temperature for a long time.

DID YOU KNOW? Food-borne illness (FBI) is the official name for what is popularly known as ‘food poisoning’. There are actually 2 types of food-borne infections:

  1. food-borne infections caused by ingesting pathogens (bacteria, viruses, etc.)
  2. food poisoning caused by eating a bacterial toxin already present in the food.


Salmonellabacteria mainly infect the digestive tract in humans and cause gastroenteritis.

The symptoms appear 6 to 72 hours after ingesting the bacteria:

  • fever
  • diarrhea
  • abdominal cramps
  • nausea, cramps, vomiting
  • headache.

Salmonellosis lasts an average of 4 to 7 days and usually heals without treatment. In frail individuals, salmonellosis can cause more serious complications, such as septicemia (infection of the blood) and meningitis (infection of the meninges).

Typhoid fever and paratyphus are caused by specific types of Salmonella that occur in endemic areas outside Europe. They are contracted when traveling to endemic countries and cause other (more serious) symptoms. 


The Salmonellabacterium is transmitted to humans via the oral route:

  • especially by eating raw or undercooked food from infected animals (meat, eggs, products based on raw eggs)
  • sometimes by eating food contaminated with the feces of an infected animal (fruits, vegetables, salads)
  • indirectly by eating healthy food that has been contaminated by another food or by water.

In rare cases, salmonellosis can also be transmitted:

  • due to inter-human contamination (i.e. between people) via the fecal-oral route (e.g. an infected person prepares food without first washing his/her hands after going to the toilet)
  • through direct or indirect contact with an infected animal (pets or companion animals, e.g. pet reptiles).


Salmonella is a bacterium that is mainly transmitted orally through food. To prevent transmission, hygiene regulations must be strictly followed, especially with regard to preparing, cooking and storing food.

  • Wash and clean:
    • wash hands after going to the toilet
    • wash your hands before cooking
    • wash your hands after handling high-risk foods (raw meat, eggs, fruit, unwashed vegetables)
    • clean the work surface and utensils used to prepare the high-risk food (raw meat, eggs, fruit and unwashed vegetables)
    • wash fruit and vegetables thoroughly
    • clean the refrigerator regularly (once a month))
    • wash your hands after contact with animals that may be carriers of Salmonella.
  • Cook correctly: make sure that meat, especially pork, poultry and minced meat, is well cooked (at least 65°C for 5 to 6 minutes).
  • Keep as cool as possible:
    • put food in the refrigerator (4°C) as soon as possible after purchase
    • keep eggs in the refrigerator
    • keep preparations containing raw eggs (mayonnaise, chocolate mousse, ice cream) in the refrigerator
    • raw egg-based preparations should be prepared just before eating
    • defrost food in the refrigerator or microwave (not at ambient temperature).
  • Keep raw food separate from prepared food:
    • use a different cutting board for cutting meat and shellfish
    • use a different knife for cutting meat and shellfish
    • keep raw meat and eggs separate from other foods, in your grocery bag and in the refrigerator.


The doctor will take a sample of the patient’s stool and send it to a laboratory for a culture (coproculture). If the Salmonellabacterium is isolated in the stool, the diagnosis of salmonellosis will be confirmed.

The laboratory will send the human bacterial strain to the Bacterial Diseases Department at Sciensano, which compares it with food-borne strains before confirming the source of infection.

The diagnosis of typhoid fever and paratyphoid will be confirmed by isolating the bacteria in the patient’s blood or stool.

DID YOU KNOW? Salmonellosis usually heals spontaneously after a few days. This means that very few people with salmonellosis go to see a doctor. As a result, the statistics for diagnosed cases of salmonellosis in Belgium do not reflect the actual number of cases of salmonellosis.

Risk groups

Anyone can get salmonella but, in some vulnerable or frail people, the disease can worsen due to dehydration from diarrhea or as a result of invasive salmonellosis:

  • Young children
  • the elderly
  • immuno-suppressed people.

DID YOU KNOW? People who take antacids or antibiotics, who are malnourished or suffer from certain diseases (achlorhydria or hypochlorhydria, cancer) may be particularly susceptible to Salmonella.


Salmonellosis is usually a benign disease that does not require any special treatment. Care should be taken to avoid dehydration by drinking plenty of water.
Invasive salmonellosis in high-risk individuals is treated with antibiotics.

Typhoid fever and paratyphoid are always treated with antibiotics.

Due to the overuse of antibiotics in humans as well as animals, several Salmonellastrains have developed resistance to a number of antibiotics. Resistant bacteria in animals can reach humans through food and cause food poisoning that is difficult to treat.

At the moment, the first-line antibiotics prescribed for salmonellosis continue to be effective. Therapeutic failure is rare, but it is possible.

Typhoid fever and paratyphus

The Salmonellabacteria responsible for typhoid fever and paratyphoid fever only occur in humans. The bacterium is transmitted through water or food that is contaminated by infected feces from humans. The main cause of fecal-oral transmission diseases is a lack of hygiene and drinking water. To avoid such transmission, it is especially important for people to wash their hands after fecal contact and before handling food. In developing countries or countries where the water is not always drinkable, one must be careful with water, as well as with food that has been rinsed with non-potable water.

There is a vaccine against typhoid fever that is recommended for travelers to endemic areas from the age of 2. Vaccination does not provide complete protection and does not replace precautions that need to be taken with regard to water and food.

Typhoid fever and paratyphus:

  • are diseases that rarely occur in Europe
  • are more common in developing countries
  • in Europe are mostly from imported cases after a stay in an endemic area (developing countries) 
  • can be fatal if not treated with antibiotics (10% deaths).

Sciensano helps to diagnose cases of salmonellosis, identifies the sources of contamination, checks products, monitors the evolution of salmonellosis in Belgium and studies Salmonella bacteria’s susceptibility to antibiotics.

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