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Causes, signs, and symptoms of Foodborne Illnesses

While there are many different causes of foodborne illness there are 4 pathogens that cause many of the cases. A pathogen is an agent causing disease, especially a living microorganism such as a bacteria, virus, or fungus. The 4 most common pathogens are:

  • E.coli: can cause kidney failure in young children and infants.
  • Salmonella: can lead to reactive arthritis and serious infections.
  • Listeria: can cause meningitis and stillbirths.
  • Campylobacter: may be the most common cause for Guillain-Barre (gee-on ba-ray) syndrome. (Guillain-Barre syndrome is a disorder in which the body's immune system attacks part of the nervous system. This syndrome results in tingling and weakness in the muscles and can lead to temporary paralysis.

Pathogens can grow on certain foods that have become unsafe. These foods are known as potentially hazardous foods. A potentially hazardous food is when bacteria, fungus, and viruses (microorganisms) grow rapidly. These foods have a characteristic that allow microorganisms to thrive, making them at risk of being contaminated.

Potentially hazardous foods usually contain one or more of these characteristics:

  • High in moisture
  • High in protein
  • Have a neutral or slightly acidic pH

The list below contains some, but not all potentially hazardous foods. The list gives you an idea of what kinds of foods can be hazardous.

Milk and milk products

Cooked rice or beans

Raw eggs


Meat, beef, pork, lamb


Baked or boiled potatoes


Sliced melons

Signs and Symptoms of Foodborne Illness

Symptoms of foodborne illness are similar to symptoms of the flu but are caused by bacteria in food rather than the flu virus.

Symptoms often include:

  • Nausea
  • Diarrhea
  • Headaches
  • Vomiting
  • Abdominal Cramping

It is sometimes difficult to tell the difference between the flu and a foodborne illness unless a doctor diagnoses it or the food that was eaten has been tested and results indicate that the food is contaminated.

Generally, foodborne illness can happen 30 minutes to 3 weeks after eating the contaminated food but most often occurs within 48 hours and the symptoms usually pass within 24 to 48 hours. Foodborne illness often causes diarrhea or vomiting or any or all of the symptoms listed above.

Populations Most at Risk:

Certain groups of people are at increased risk of getting a foodborne illness. It is especially important for these populations to follow food safety principles to ensure the safety of their food.

These populations include:

  • Infants and preschool-age children
  • Pregnant women
  • Elderly people
  • People taking certain medications, such as antibiotics and immunosuppressant (drugs that weaken the immune system).
  • People who are ill (recently had major surgery, organ-transplant recipients, or who have pre-existing or chronic illness).