By John Spinosa, M.D., Ph.D. Scripps Memorial Hospital La Jolla
Tomatoes, ground beef, spinach and lettuce. Over the past few years, all of these foods have been associated with some type of illness—and unfortunately, you don’t know they’re not safe to eat until the nausea, cramping and other symptoms have started.
Foodborne illnesses result from consuming contaminated foods or beverages. According to the CDC, 76 million Americans get sick from contaminated food each year, and the effects can be as mild as an upset stomach or as severe as a life-threatening infection. Fortunately, most cases are limited to a few days of vomiting, diarrhea, cramping and other stomach-related discomforts.
How does food contamination occur? In some cases, food can be contaminated during production; for example, beef and chicken may become tainted by bacteria from the animals’ intestines during processing. Fruits and vegetables can be infected if they are washed or irrigated with contaminated water. Bacteria can be spread to food by infected people who handle it, and contaminated cutting boards and utensils can also spread germs.
Cooking usually kills harmful bacteria, but even cooked foods can be infected if it comes into contact with contaminated raw foods.
There are more than 200 different foodborne diseases. Most are caused by a variety of bacteria, viruses, and parasites; three of the most common are those caused by the bacteria Campylobacter, Salmonella, and E. coli O157:H7.
Campylobacter is found on most raw poultry meat. Cooking kills the bacteria, but eating undercooked poultry or other food that has been in contact with contaminated juices from raw poultry can lead to infection. Campylobacter is a leading cause of diarrhea, and also causes fever and abdominal cramps.
Salmonella is another type of bacteria commonly found in the intestines of birds, reptiles and mammals, and can spread to people through a variety of foods if the food comes into contact with contaminated feces. Salmonella infection usually causes fever, diarrhea and abdominal cramps. In persons with poor health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections.
E. coli O157:H7 is also found in the intestines of some animals, including cows, and is typically spread through food or water that has become contaminated. E. coli often causes severe and bloody diarrhea and painful abdominal cramps, usually without a fever. In less than 5% of cases, a complication called hemolytic uremic syndrome (HUS) can occur, and may cause temporary anemia and kidney failure.
When to call your doctor
Call your doctor if you have diarrhea and any of the following symptoms:
- fever over 101.5 F, measured orally
- blood in the stools
- prolonged vomiting with inability to keep fluids down
- signs of dehydration, including a decrease in urination, a dry mouth and throat, and feeling dizzy
- diarrhea that lasts more than 3 days
Treatment for foodborne illness depends on the type of illness and the symptoms it causes. Many diarrheal illnesses will improve in two or three days. Diarrhea or vomiting can lead to dehydration, so replacing lost fluids and electrolytes and keeping the body rehydrated are key. If diarrhea is severe, you doctor may recommend an oral rehydration solution. Do not use sports drinks to rehydrate, as they do not adequately replace lost fluids.
Preventing foodborne illness
You can take a few basic steps to reduce your risk of contracting a foodborne illness:
- Wash your hands with soap and water before preparing food, and make sure others who come into contact with the food do the same.
- Cook meat, poultry and eggs thoroughly. Use a meat thermometer to measure the internal temperature of meat.
- Avoid cross-contaminating foods. Wash your hands, utensils, and cutting boards after touching raw food. Wash plates that held raw meat immediately—do not use them for cooked meat, vegetables or other food without washing them first.
- Refrigerate leftovers promptly. Divide large portions into several smaller containers to enable them to cool more quickly.
- Rinse fresh fruits and vegetables in clean running water to remove visible dirt.
- Remove and discard the outer leaves of lettuce or cabbage.
John Spinosa, M.D., Ph.D., is a pathologist and chief of staff at Scripps Memorial Hospital La Jolla. For more wellness tips or for a physician referral, please call 1-800-SCRIPPS (1-800-727-4777).