See tables of illnesses, hospitalizations, and deaths caused by all 31 pathogens.

Tracking Trends

Tracking trends in foodborne illness since 1996, the Foodborne Diseases Active Surveillance Network (FoodNet) has conducted active, population-based surveillance for 9 laboratory-confirmed infections commonly transmitted through food including:

• Campylobacter
• Cryptosporidium
• Cyclospora
• Listeria
• Salmonella
• Shigella
• Shiga toxin-producing Escherichia coli O157 and non-O157
• Vibrio
• Yersinia 

FoodNet is a collaborative program among the CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee, and selected counties in California, Colorado, and New York to find out about all infections diagnosed in residents of these areas.

Common Pathogens That Cause Foodborne Infections

The most common day foodborne infections from the 2011 Estimates of Foodborne Illness and from those tracked by FoodNet include those caused by:

• Campylobacter is a bacterial pathogen that causes fever, diarrhea, and abdominal cramps. It is the most commonly identified bacterial cause of diarrheal illness in the world. These bacteria live in the intestines of healthy birds, and most raw poultry meat has Campylobacter on it. Eating under cooked chicken, or other food that has been contaminated with juices dripping from raw chicken is the most frequent source of this infection (tracked by FoodNet).
• Clostridium perfringens (C. perfringens) is a spore-forming gram-positive bacterium that is found in many environmental sources as well as in the intestines of humans and animals. C. perfringens is commonly found on raw meat and poultry. It can survive in conditions with very little or no oxygen. C. perfringens produces a toxin that causes illness.
• Norovirus (previously called Norwalk-like virus) is an extremely common-day cause of foodborne illness, though it is rarely diagnosed, because the laboratory test is not widely available. It causes an acute gastrointestinal illness, usually with more vomiting than diarrhea, that generally resolves within three days. Unlike many foodborne pathogens that have animal reservoirs, norovirus spreads primarily from one infected person to another, often through contaminated food, water, or environmental surfaces. Infected kitchen workers can contaminate a salad or sandwich as they prepare it, if they have the virus on their hands. Sewage discharge into coastal growing waters have contaminated oysters before they are harvested.
• Salmonella is a bacterium that is widespread in the intestines of birds, reptiles and mammals. It can spread to humans via a variety of different foods of animal origin. The illness it causes, salmonellosis, typically includes fever, diarrhea and abdominal cramps. In persons with poor underlying health or weakened immune systems, it can invade the bloodstream and cause life-threatening infections (tracked by FoodNet). For more information on Salmonella, please visit:
  • Salmonella
  • Salmonella enteritidis
  • Salmonellosis (Salmonella infection)
  • Salmonella typhi (Typhoid Fever)
• The Shigella germ is actually a family of bacteria that can cause diarrhea in humans. They are microscopic living creatures that pass from person to person. Shigella were discovered over 100 years ago by a Japanese scientist named Shiga, for whom they are named. There are several different kinds of Shigella bacteria: Shigella sonnei, also known as "Group D" Shigella, accounts for over two-thirds of shigellosis in the United States. Shigella flexneri, or "group B" Shigella, accounts for almost all the rest. Other types of Shigella are rare in this country, though they continue to be important causes of disease in the developing world. One type found in the developing world, Shigella dysenteriae type 1, can cause deadly epidemics (tracked by FoodNet).

Other Routes & Causes

Some common day diseases are occasionally foodborne, even though they are usually transmitted by other routes. These include infections caused by Shigella, hepatitis A, and the parasites Giardia lamblia and Cryptosporidia. Even strep throats have been transmitted occasionally through food. In addition to disease caused by direct infection, some foodborne diseases are caused by the presence of a toxin in the food that was produced by a microbe in the food.

• For example, the bacterium Staphylococcus aureus can grow in some foods and produce a toxin that causes intense vomiting.
• The rare but deadly disease botulism occurs when the bacterium Clostridium botulinum grows and produces a powerful paralytic toxin in foods. These toxins can produce illness even if the microbes that produced them are no longer there.
• Other toxins and poisonous chemicals can cause foodborne illness. People can become ill if a pesticide is inadvertently added to a food, or if naturally poisonous substances are used to prepare a meal. Every year, people become ill after mistaking poisonous mushrooms for safe species, or after eating poisonous reef fishes.

Related Links

• Most Common Day Foodborne Diseases From the CDC
• Preliminary FoodNet Data on the Incidence of Foodborne Illnesses
• Surveillance for Foodborne Disease Outbreaks