Food-borne illness: First aid

By Mayo Clinic Staff

All foods naturally contain small amounts of bacteria. But poor handling of food, improper cooking or inadequate storage can result in bacteria multiplying in large enough numbers to cause illness. Parasites, viruses, toxins and chemicals also can contaminate food and cause illness.

Signs and symptoms of food poisoning vary with the source of contamination, and whether you are dehydrated or have low blood pressure. Generally they include:

  • Diarrhea
  • Nausea
  • Abdominal pain
  • Vomiting
  • Dehydration

With significant dehydration, you might feel:

  • Lightheaded or faint, especially on standing
  • A rapid heartbeat

Whether you become ill after eating contaminated food depends on the organism, the amount of exposure, your age and your health. High-risk groups include:

  • Older adults. As you get older, your immune system may not respond as quickly and as effectively to infectious organisms as it once did.
  • Infants and young children. Their immune systems haven't fully developed.
  • People with chronic diseases. Having a chronic condition, such as diabetes or AIDS, or receiving chemotherapy or radiation therapy for cancer reduces your immune response.

If you develop food poisoning:

  • Rest and drink plenty of liquids.
  • Generally, anti-diarrheal medications should be avoided because they may slow elimination of organisms or toxins from your system. If in doubt, check with your doctor about your particular situation.
  • Infants or young children should not be given anti-diarrheal medications because of potentially serious side effects.

Foodborne illness often improves on its own within 48 hours. Call your doctor if you think you have a foodborne illness and your symptoms have lasted longer than two or three days. Call immediately if blood appears in your stools.

Seek emergency medical assistance if:

  • You have severe symptoms, such as severe abdominal pain or watery diarrhea that turns very bloody within 24 hours.
  • You belong to a high-risk group.
  • You suspect botulism poisoning. Botulism is a potentially fatal food poisoning that results from the ingestion of a toxin formed by certain spores in food. Botulism toxin is most often found in home-canned foods, especially green beans or tomatoes. Signs and symptoms of botulism usually begin 12 to 36 hours after eating the contaminated food and may include headache, blurred vision, muscle weakness and eventual paralysis. Some people also have nausea and vomiting, constipation, urinary retention, difficulty breathing, and dry mouth. These signs and symptoms require immediate medical attention.
Feb. 07, 2015