There are many different germs that can contaminate foods. In fact, we have identified more than 250 different foodborne diseases. Most of them are infections, which can be caused by a variety of different bacteria, viruses, and parasites. Some of these illnesses are caused by toxins or chemicals produced by the germ, rather than a true infection with the germ itself.
Here are the most common causes of food poisoning:
Germ | Common Food Source | Typical Symptoms | Timing of Symptoms |
Norovirus | Leafy greens, fresh fruits, shellfish (such as oysters) | Diarrhea, nausea, vomiting, stomach pain (can be severe) | Start within 12-48 hours Lasts 1-3 days |
Salmonella | Undercooked poultry or eggs, unpasteurized milk or juice, contaminated raw fruits and vegetables | Diarrhea, fever, stomach cramps, vomiting | Start within 12-72 hours Severe symptoms improve within 1 week but some diarrhea may last for much longer |
Clostridium perfringens | Cooked foods that are cooled and held, then served without reheating, especially roasts of beef or poultry | Diarrhea, stomach cramps | Start suddenly within 6-24 hours Last for less than 24 hours |
Campylobacter | Undercooked poultry, unpasteurized milk, contaminated water or produce | Diarrhea (often bloody), stomach cramps, fever | Start within 2-5 days Last about 1 week |
Staphylococcus aureus (symptoms caused by a toxin produced by the Staph bacteria) | Foods that are not cooked after handling, including sliced meats, pastries, sandwiches. | Nausea, vomiting, stomach cramps, diarrhea | Start suddenly within 30 minutes to 8 hours Last no longer than 24 hours |
There are other germs that are not nearly as common, but when they do cause illness, they can be severe, and even life-threatening. These germs include:
- Clostridium botulinum (botulism)
- Listeria
- E. coli
- Vibrio
- High fever (temp over 102 degrees F)
- Blood in your bowel movements
- Signs of dehydration (marked decrease in urination, very dark urine, feeling dizzy when standing, extremely dry mouth and throat)
- Diarrhea which lasts for more than 3 days
If you have any questions about food poisoning, please log into your account and send us your question. We are here to help.
Dr. Anita Bennett MD - Health Tip Content Editor