Bacteria and Foodborne Illness

Foodborne illness results from eating food contaminated with bacteria (or their toxins) or other pathogens such as parasites or viruses. The illnesses range from upset stomach to more serious symptoms, including diarrhea, fever, vomiting, abdominal cramps, and dehydration. Although most foodborne infections are undiagnosed and unreported, the Centers for Disease Control and Prevention estimates that every year about 76 million people in the United States become ill from pathogens in food. Of these, about 5,000 die.

Causes

Harmful bacteria are the most common causes of foodborne illnesses. Some bacteria may be present on foods when you purchase them. Raw foods are not sterile. Raw meat and poultry may become contaminated during slaughter. Seafood may become contaminated during harvest or through 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 Escherichia coli (E. coli) O157:H7. Contamination can occur during growing, harvesting, processing, storing, shipping, or final preparation. Sources of contamination are varied; however, these items are grown in the soil and therefore may become contaminated during growth or through processing and distribution. Contamination may also occur during food preparation in the restaurant or in the person's kitchen.

When food is cooked and left out for more than 2 hours at room temperature, bacteria can multiply quickly. Most bacteria grow undetected because they do not produce an "off" odor or change the color or texture of the food. 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 the bacteria.

Symptoms

In most cases of foodborne illness, symptoms resemble intestinal flu and may last a few hours or even several days. Symptoms can range from mild to serious and include

· abdominal cramps

· nausea

· vomiting

· diarrhea

· fever

· dehydration

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Risk Factors

Some people are at greater risk for bacterial infections because of their age or immune status. Young children, pregnant women and their fetuses, the elderly, and people with lowered immunity are at greatest risk.

Complications

Some micro-organisms, such as Listeria monocytogenes and Clostridium botulinum, cause far more serious illness than vomiting or diarrhea. They can cause spontaneous abortion or death.

In some people, especially children, hemolytic uremic syndrome (HUS) can result from infection by a particular strain of bacteria, E. coli O157:H7, and can lead to kidney failure and death.