The Most Common Causes of Food Poisoning (and How to Treat It)

updated May 1, 2019
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(Image credit: Emma Christensen)

When the weather warms up, is there any lunch better than a picnic lunch? Ice-cold drinks, homemade sandwiches, and creamy potato salad, enjoyed for hours in the sunshine … wait. How long has that potato salad been sitting there in the sun?

Sadly, warmer weather also means more opportunities for the bacteria and viruses that cause foodborne illnesses to thrive on food that has been improperly prepared or stored. From shellfish to undercooked poultry, here are the most common food poisoning culprits and — if it’s already too late for you — some advice for treating foodborne illnesses.

The 6 Most Common Causes of Food Poisoning

According to the U.S. Department of Health & Human Services, the following organisms cause the most illnesses, hospitalizations, and deaths in the United States:

  • Salmonella: Found in contaminated eggs, poultry, meat, unpasteurized milk or juice, cheese, contaminated raw fruits and vegetables (alfalfa sprouts, melons), spices, and nuts
  • Norovirus: Found in produce, shellfish, ready-to-eat foods touched by infected food workers (salads, sandwiches, ice, cookies, fruit)
  • Campylobacter: Found in raw and undercooked poultry, unpasteurized milk, contaminated water
  • E. coli: Found in contaminated food, especially undercooked ground beef, unpasteurized (raw) milk and juice, soft cheeses made from raw milk, and raw fruits and vegetables (such as sprouts)
  • Listeria: Found in ready-to-eat deli meats and hot dogs, refrigerated pâtés or meat spreads, unpasteurized (raw) milk and dairy products, soft cheese made with unpasteurized milk (such as queso fresco, feta, Brie, Camembert), refrigerated smoked seafood, raw sprouts
  • Clostridium perfringens: Found in beef, poultry, and gravies, which are prepared in large quantities and kept warm for a long time before serving

Symptoms can appear in as little as 30 minutes after consuming the contaminated food, and generally include vomiting, diarrhea, abdominal cramps, and nausea.

When should you see a doctor? The CDC has a list of symptoms to watch for, including a fever over 101.5°F, signs of dehydration (dry mouth and throat, decrease in urination, and feeling dizzy when standing up), and illness that lasts more than three days.

Certain high-risk groups should seek medical attention immediately: infants, young children, pregnant women, older adults, and people with weakened immune systems (such as those with cancer, HIV/AIDS, diabetes, kidney disease, and transplant patients).

(Image credit: Jessica Goldman Foung)

How to Treat a Foodborne Illness

Different foodborne illnesses require different treatments depending on their symptoms, but if you are experiencing vomiting and diarrhea, you may be at risk for dehydration, so drinking fluids is important. In more severe cases, drinking an oral rehydration solution such as Ceralyte, Pedialyte, or Oralyte can help prevent dehydration. (The CDC doesn’t recommend sports drinks like Gatorade, which don’t replace the fluid and electrolyte losses correctly.)

Once you are ready to start eating again, you may want to try the BRAT diet — bananas, rice, applesauce, and toast — the bland-food diet historically prescribed for gastrointestinal distress. Other gentle foods to try include bone broth, soup, fruit juices, and soft fruits and vegetables.

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