Food Borne Illness
by Cecilia Mullen, R.N.C., N.P.
June 30, 2000
This time of year, we think about the long hot days of summer, which include cookouts, picnics, fairs, and other outdoor gatherings. The combination of warm temperatures and food can result in bacteria growth that cause what's commonly referred to as food poisoning.
The Center for Disease Control recently estimated that 76 million cases of food borne illnesses occur each year in the United States. Unfortunately the causative bacteria cannot be identified in over 80% of cases. This means that treatment must be generally broad and symptom related, and prevention must also be general.
The bacteria most commonly thought to cause food borne illnesses are Norwalk-like viruses, campylobacteria and Salmonella. These account for an estimated 90% of all food borne illnesses.
Fortunately, most people get better without specific treatment. For the most part, it is recommended to maintain a high fluid intake for as long as you continue to have symptoms. People who are most susceptible to serious effects are the very young, the very old, and the immunocompromised (people whose immune system is down such as those with AIDS, or those who have undergone chemotherapy or radiation therapy or organ transplants).
Norwalk-like Viruses
These viruses, the most common cause of viral gastroenteritis, are fairly benign. They are easily spread when small amounts of human feces taint food. Raw shellfish or improperly steamed clams or unwashed salad ingredients are frequently the cause. People can pass the virus to another person or to food. A person becomes ill within 24-48 hours, experiencing abdominal pain, watery diarrhea, nausea and vomiting. The majority feel better within 24-60 hours and rarely need hospitalization.
Campylobacteria
This bacteria usually causes a diarrheal syndrome and fever, which lasts for more than 2-3 days. Symptoms include abdominal pain, cramping, nausea, and vomiting. Bloody diarrhea may occur as well. Symptoms appear 2-5 days after exposure and may linger 7-10 days. Contact with raw poultry is a primary source of infection. Fewer than 500 bacteria organisms can cause illness -- one drop of juice from raw chicken is all it takes. People generally get better on their own and should drink fluids to avoid dehydration.
Salmonella
Generally found in raw and undercooked eggs, Salmonella can also be found in a variety of foods. People begin to feel symptoms 6-48 hours after ingestion. Symptoms are mainly abdominal cramping and diarrhea and can also be accompanied by fever, headache, nausea, and vomiting. Most people will recover from Salmonellosis without treatment.
Other bacteria
Certain bacterial strains can be more harmful but fortunately are more rare: Listeria, toxoplasma, and certain E.coli strains to name a few.
Listeriosis is a particular threat to pregnant women, newborns, the elderly, and the immunocompromised. The organism usually exists in raw milk, soft cheeses such as Brie and ready to eat meats such as hot dogs. People at risk should avoid high-risk foods or cook foods until hot, reaching 180 degrees Fahrenheit.
Toxoplasma is particularly devastating to fetuses and immunocompromised individuals. Food sources are raw or undercooked lamb, pork or venison. Another common source of this parasite is the cat litter box. Most healthy individuals will not experience symptoms or will develop mild flu-like illness. Fetuses or immunocompromised individuals can develop permanent and/or recurrent neurologic deficits.
E. Coli contamination results when cow waste contaminates meat or water sources. Undercooked hamburgers are the biggest risk. Hamburgers must be cooked until the inside reaches at least 160 degrees Fahrenheit. (Color change does not reliably indicate adequate cooking, use a thermometer.) E. Coli infections have also been associated with alfalfa sprouts, drinks and ice made with contaminated water, lettuce, raw milk, and unpasteurized juices. Symptoms include severe abdominal cramping and watery, bloody diarrhea and may occur 2-5 days after ingestion.
Treatment
If you experience mild to moderate symptoms of food poisoning and are otherwise healthy, it is important to drink large amount of clear liquids such as water, ginger ale, Gatorade, Kool-Aid (any liquid that is "see through"). Avoid dairy products. Don't worry about lack of appetite or food intake for the first 24-48 hours. If you are unable to keep fluids down, you must see your provider, as you may need I.V. fluids.
Any individual who falls into a high-risk group such as infants, pregnant women, the elderly, or the immunocompromised should see their physician or provider at the onset of symptoms, since complications can develop quickly. Anyone who experiences symptoms for more than 48 hours or who has severe symptoms or bloody diarrhea, should be evaluated immediately.
Prevention
Although food borne illnesses cannot be completely prevented, simple precautions can be taken to reduce its occurrence.
- Do not allow food to stand for long periods at warm temperatures. Keep it hot or cold.
- Wash your hands and food utensils frequently.
- Avoid cross contamination by washing any surface that contacts raw meat and throw away meat marinade that has contacted raw meat.
- Wash fruits, vegetables with running cold water. Salad sold in premix bags should be washed before eating. Melons and grapefruits should be washed before cutting.
- Wash hands... again! And avoid using a kitchen towel to dry your hands, as this harbors bacteria.
- Cook foods thoroughly and avoid unpasteurized foods. High-risk individuals should avoid unpasteurized juices sold in stores.
- Consider irradiated meats for improved food safety, particularly if you are in a high-risk group. Irradiation eliminates organisms without causing harm to the people who eat the food.
Remember, most food borne illness stems from poor hygiene and originates at home, so careful protection is key.
ENJOY YOUR SUMMER!
Cecilia Mullen is a nurse practitioner at Granite Medical Group. The information in this column is not intended to diagnose individual conditions. Readers should see their own doctors about specific problems.