Foodborne Bacteria

Cooking Schools Guide: Foodborne Bacteria

According to the CDC, 1 in 6 Americans contract an illness from the food they eat every year, which translates into 48 million cases. While the vast majority do receive medical attention from a hospital, 3,000 of those afflicted with “food poisoning” die from the infection. The CDC goes on to state that 80 percent of the pathogens that cause foodborne illness are unknown, including 56 percent of those that eventually result in death. However, researchers do know that a significant portion of these illness are caused by bacteria; salmonella, clostridium perfringens, and campylobacter account for around 10 percent of cases each. Even though the majority of foodborne illnesses are a result of viruses, bacteria outbreaks are still a major concern.

This page will focus on food poisoning caused by bacteria in particular, although much of the information about salmonella and other pathogens that is available online comes from government and medical websites that discuss foodborne illness in general. The Internet resources gathered in these sections were selected for their medical authority, but also for their accessibility to lay readers, including the average patient. However, any visitors to these sites who are concerned that they may actually have food poisoning should seek medical help rather than relying on self-diagnosis.

Foodborne Bacteria Defined

There are several different types of foodborne bacteria, but they all work in similar ways: certain microorganisms that grow on meat can, if still numerous after preparation, continue to grow inside a human or animal’s intestinal tract and produce toxins. These toxins, rather than the bacteria itself (the human body is host to numerous benign organisms), are what cause patients to become ill. A fact sheet from Colorado State University delves into more detail, and describes the symptoms, whose severity depends on the resistance of the bacteria to antibiotics and the condition of the infected patient’s immune system. These symptoms are echoed by the National Digestive Diseases Information Clearinghouse: 1) diarrhea, 2) vomiting, 3) dehydration, 4) nausea, 5) fever, and 6) abdominal pain. The Mayo Clinic adds headache and muscle pain to the list.

Salmonella, known medically as salmonellosis according to the National Institute of Allergy and Infectious Diseases, is responsible for 40,000 reported cases of foodborne illness in the U.S. and is especially dangerous to babies, the elderly, and patients with weak immune systems, such as those living with AIDS. The USDA Food Safety and Inspection Service’s FAQ explains that there are more than 2,300 different kinds of salmonella, although the two most common types in the U.S. are Enteritidis and Typhimurium. The latter is infamous for its resistance to antibiotics. Other forms of foodborne bacteria include the following:

  • Camplyobacter usually takes between 2 to 5 days to incubate and can then cause illness that lasts for more than a week, or as little as 2 days. Camplyobacter is especially common in poorly prepared poultry and unsanitary water supplies, according to the World Health Organization.
  • Clostridium perfringens is a form of bacteria whose spores can survive low cooking temperatures and grow in environments with little to no oxygen, and whose toxins cause sickness for 1 to 2 days. A fact sheet from the University of Florida reveals more.
  • Staphylococcus aureus, like most foodborne bacteria are found in all kinds of meat, although egg and dairy products, including pastry fillings, are common culprits as well. The bacteria naturally exist on the hair and skin of animals (including people) without causing infection. Illness from the microorganism usually only lasts 1 to 2 days. Detailed information can be found in Todar’s Online Textbook of Bacteriology, although the FDA’s Bad Bug Book focuses more on the foodborne variety.

The American Medical Association’s Foodborne Illness Table: Bacterial Agents maintains a list of most known bacteria and provides essential information (incubation period, types of food that carry them, treatment, etc.) for each. In many cases, the AMA has no specific treatment for foodborne illness other than to allow the body’s immune system to destroy the bacteria and to replace water lost through diarrhea and vomiting.

Pathogenecity

Foodborne bacteria spread through unsanitary conditions, which can occur at any point in production, from the raising of livestock (many forms of these infectious organisms occur naturally in animal feces) to storage to cooking. Bacteria in general are single-cell organisms, some of the most basic lifeforms on Earth. While the vast majority do not harm human beings — and some are even beneficial — the nature of bacteria is to divide rapidly, a process that can produce toxins as a byproduct. Because bacteria can attach themselves to human tissues using tiny hairs called fimbriae (also known as pili) and can move around using flagella, they are adept at surviving in hostile environments, including the human body. This information comes from Dr. Trudy M. Wassenaar’s article, Bacterial Pathogenicity, from the Museum of Bacteria.

Prevention

The USDA’s guide on the Basics for Handling Food Safely recommends that prevention begin at the grocery store. Shoppers should purchase frozen items last so that the products do not have time to thaw in the shopping cart (bacteria tend to grow in warm, moist conditions). Consumers should check packaging for expiration dates and to ensure there are no punctures or tears, especially of meat products. Once at home, buyers should store meet, especially poultry and fish, at 40 degrees Fahrenheit or below, or at less than zero degrees for food that is not prepared within 48 hours.

The USDA’s pamphlet corresponds with the university-produced guide, You Can Prevent Foodborne Illness, by recommending that most bacteria-prone foods (most meats) be cooked until the inner portions are at 165 degrees or above and that such foods be kept at over 140 degrees until served. Different kinds of meats require different cooking temperatures and provide different indicators of readiness, however. Fish, for example, should be cooked until the meat can be flaked with a utensil with no trouble. For more information, the U.S. federal government’s Food Safety site provides frequently updated content about proper handling of food products.

Finally, washing one’s hands with soap for 20 seconds or more, especially after using the restroom, is vital, according to a pamphlet by the University of Georgia’s College of Family and Consumer Sciences, which also recommends adding one tablespoon of bleach to every gallon of water used in washing dishes to eliminate bacteria. Finally, consuming bottled water in areas where tap or well water is suspect, such as in developing countries, is especially important as well.

Additional Resources

  • The American Medical Association provides a number of guides for physicians, nurses, and other medical professionals, including “patient scenarios” about salmonella that are resistant to antibiotics and other types of infections.
  • The Centers for Disease Control and Prevention concentrate on providing statistics (including those mentioned in the introduction to this page), but also offers a FAQ with practical information.
  • The Center for Foodborne Illness Research and Prevention was established in 2006 as a non-profit advocacy group to ensure proper government regulation of the food industry to prevent disease caused by bacterial, virulent, and toxic contamination.

Image was originally from the National Institutes of Health, but was acquired via Wikimedia Commons.