The recent outbreak of a dangerous bacterial strain in bagged spinach has made headlines for its rapid spread across the country. But foodborne illness affects millions nationwide each year. It is therefore important for consumers to consider the quality and safety of the food we eat each day.
Foodborne illness results from eating food contaminated with bacteria, bacterial toxins or other pathogens such as parasites or viruses. The illnesses can range from an upset stomach to more serious symptoms including diarrhea, fever, vomiting, abdominal cramps and dehydration.
Most cases of foodborne illness can be prevented through proper cooking or processing of food. However, some bacteria grow undetected because they do not produce an odor or change the color or texture of the food. Although most foodborne infections remain undiagnosed and unreported, the CDC estimates that every year about 76 million people in the United States become ill from pathogens in food and about 5,000 die from their illness.
The recent outbreak of E. coli in spinach has sickened almost 190 in 26 states and Canada, causing one fatality.
Harmful strains of common bacteria are the most common causes of foodborne illnesses. Raw foods are not sterile and are susceptible to bacterial contamination from a variety of sources.
Animal products are most easily infected with a variety of pathogens. Raw meat and poultry may become contaminated during slaughter. Seafood can be contaminated during harvest or processing. One in 20,000 eggs may be contaminated with Salmonella inside the egg shell.
Produce such as lettuce, tomatoes, sprouts and melons can become contaminated with Salmonella, Shigella or the E. coli strain O157:H7. Natural farming conditions are generally not sterile and leave many opportunities for pathogens to be introduced into fresh produce.
The recent E. coli outbreak was likely caused by groundwater contaminated with infected cow manure. The O157:H7 strain of E. coli lives in the bovine digestive tract and is harmless to cows.
An important source of contamination may arise during food storage and preparation in the home or restaurant. Working in a kitchen can introduce new infectious agents or trigger existing pathogens to further multiply.
The single greatest danger in the kitchen is cross-contamination, which is the introduction of pathogens from one source, often meat or poultry, into other foods, such as uncooked vegetables. It is essential to use separate equipment for preparing raw meat, poultry and seafood and to wash it thoroughly after use.
Bacteria thrive even on cooked food if it is left out for more than two hours at room temperature. Because most bacteria multiply rapidly between 40a1F and 140a1F, it is essential to keep food out of this "danger zone."
Freezing food slows or stops bacteria's growth but does not destroy the bacteria. The microbes can become reactivated when the food is thawed. Refrigeration may slow the growth of some bacteria, but thorough cooking is needed to destroy many strains of bacteria completely.
In most cases, symptoms can range from mild to serious and include abdominal cramps, nausea, vomiting, diarrhea, fever and dehydration. Many cases of foodborne illness resemble an intestinal flu, but if symptoms persist there is cause for concern.
Some individuals are at greater risk for bacterial infections because of their age or health. Young children, pregnant women, the elderly and people with lowered immunity are at greatest risk.
A doctor may be able to diagnose foodborne illness from a list of what the patient has recently eaten as well as a battery of laboratory tests. Diagnostic tests for foodborne illness should include examination of the feces. A sample of the suspected food, if available, can also be tested for bacteria and their toxins as well as for other pathogens.
Most cases of foodborne illness are mild and can be treated by increasing fluid intake, either orally or intravenously, to replace lost fluids and electrolytes. In cases with gastrointestinal or neurological symptoms, people should seek immediate medical attention.
In the most severe cases, the patient may need hospitalization in order to receive supportive nutritional and pharmaceutical therapy. Maintaining adequate fluid and electrolyte balance and controlling blood pressure are important considerations when fighting off bacterial infection.
A particular danger with many foodborne illnesses is an acute reduction in kidney function, which can be a serious medical emergency. Early dialysis is crucial until the kidneys can function normally again, and blood transfusions may be needed in rare cases. It is considerably easier to prevent foodborne illness than to treat it once it arises. The key to preventing such illness is vigilance during all stages of food production, processing and preparation. People need to be aware of what they are eating and from where the food originates.
