What Are Foodborne Pathogens?

There are many foodborne pathogens. This article describes the 10 most common ones. By learning what these pathogens are, what illnesses they cause, and how infection can be prevented, people are taking proactive measures in the fight to reduce the numbers affected by these illnesses.

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Ten Foodborne Pathogens

What are foodborne pathogens?

How can you protect you and your family from them?

There are many foodborne pathogens, some more common than others. By learning what these pathogens are, what illnesses they cause, and how infection can be prevented, people are taking proactive measures in the fight to reduce the numbers affected by these illnesses. People should also keep in mind that some of these pathogens cause other types of illness as well.


Campylobacter is a type of bacterium that causes gastroenteritis, which is a type of infection that affects the intestines. It is the most common cause foodborne diarrhea in the world, even more common than Salmonella. Poultry, cows, and other warm-blooded animals are typically the hosts of this type of bacteria. Because it can be in food that comes from these sources, it is important to cook food thoroughly as heat can kill the camplyobacter bacterium. The best way to avoid infection is to prepare food in a manner that is clean and follows good basic cooking hygiene. Symptoms of infection last as long as six days and include diarrhea with and without blood, fever, nausea, headache, abdominal pain, and vomiting. In the immunosuppressed, children, and the elderly, the Camplyobacter can be deadly.

Campylobacter Fact Sheet

Clostridium botulinum

C. botulinum is the bacterium that produces a neurotoxin during its growth. It is extremely toxic and can cause illness even in microscopic amounts. When this neurotoxin is digested it can cause botulism. Botulism is a disease that paralyzes the nervous system and can result in severe illness and even death. Spores from C. botulinum can be found in seafood or on vegetables or fruit. Foods that have been improperly canned can also form the toxin.

Foodborne Illness and Disease Fact Sheet Clostridium botulinum

E. coli O157:H7

E. coli O157:H7, or Escherichia coli is a type of E. coli bacteria that produces a toxin which results in intestinal disease. The disease causes symptoms, such as diarrhea, and can last as long as one week. The disease can be life-threatening, particularly in children and older adults, as it can cause kidney disease. Often animals are the carriers of this bacterium; however, they do not become ill from it. Animals that can carry E. coli O157:H7 include, but are not limited to deer, poultry, cattle, and pigs. Humans can contract the disease by eating meat that has not been cooked properly in terms of internal temperature and handling. In addition to cooking the food properly, people must also take the proper precautions when handling and/or thawing the meat. This means thawing items in the refrigerator and washing hands after handling meat. Milk, cider, and juices should also be properly pasteurized.

E.coli 0157:H7 (PDF)

Listeria monocytogenes

Often referred to as simply Listeria, Listeria monocytogenes is a bacterium that is currently one of the top three leading causes of food poisoning-related deaths. This is a bacterium that causes an infection that is known as listeriosis. People who are most susceptible to Listeria and listeriosis are people who have a weakened immune system, pregnant women, elderly, and newborn children. Common symptoms of Listerosis may include gastrointestinal problems, including diarrhea. It almost always includes muscle aches and fever and some form of invasive infection. The specific symptoms vary, often depending on the type of person. For example, a pregnant woman will generally have symptoms such as aches, and fatigue in addition to fever. Other people who are not pregnant may also experience fever and aches, but also additional symptoms such neck stiffness, headache, and potentially convulsions.



Norovirus is a bacterium that causes extreme pain and irritation of the stomach and intestines due to inflammation. People with Norovirus are often subject to symptoms, such as severe vomiting, stomach pains, and nausea. It is caused by liquid or food items that have been contaminated by fecal matter, and can be prevented in most cases by cooking and handling food properly. When cooking food, hands should be washed prior to handling. Norovirus is highly contagious and can spread via contact with a contaminated article or item. Make sure items such as door knobs or stair rails are cleaned and disinfected regularly.

About Norovirus


Salmonella is the name of a group of bacteria that causes foodborne illness. It can be found in unpasteurized milk, and is a natural microflora found in animals, including poultry. Examples of the different types of Salmonella that cause foodborne illness include Salmonella enteritidis, which comes from eating raw eggs or partially raw eggs, and Salmonella typhimurium, which is the most common bacterium that causes foodborne sickness. Salmonella Heidelberg is associated with produce. Infection by any of the Salmonella bacteria due to the ingestion of live bacterium is known as Salmonellosis. The symptoms can be identified easily and include diarrhea, stomach pains, fever, chills, headache, and nausea. Cleanliness when handling raw food, particularly meat and eggs, can help prevent infection. Cleanliness should also extend to utensils and any items that may come into contact with food. Using pasteurized milk and properly cooking items such as meat, eggs and poultry, can prevent illness from this organism.


Staphylococcus aureus

Staphylococcus aureus is form of the bacteria that is commonly known as “staph.” This particular strain of the species is associated with food poisoning. It is produced and lives in humans and animals and can be found in the air, soil, and water. The toxins made by the bacteria are difficult to remove and are unaffected by cooking although the bacteria itself is susceptible to heat. To avoid illness from the toxin produced by S. aureus people should handle food properly and keep hands, equipment, and surfaces clean. Foods should also be properly refrigerated, typically at 40 degrees Fahrenheit or lower. Meat, eggs, poultry, and items made from these foods, such as egg or chicken salad, are common sources of illness due to S. aureus. Cream-filled food items, such as éclairs, milk, and dairy products are also potentially harmful if mishandled. Rarely is food poisoning from S. aureus deadly.

Bad Bug Book – Including Staphylococcus aureus (PDF)


Shigella is a family of bacteria that was discovered over 100 years ago. In the United States, there are two common groups of the bacteria that cause the most problems: Group D Shigella and Group B Shigella. Group D, which is Shigella sonnei, is responsible for more than two-thirds of the disease known as Shigellosis. Shigellosis is a disease that is infectious and causes symptoms that include diarrhea, stomach cramping, and fever. Group B shigella is responsible for the country’s remaining cases of shigellosis. It is in human stool and is generally passed from unclean hands of an infected person to the mouth of someone who isn’t infected. An example of this would be a person preparing food without properly washing his or her hands. Vegetables grown and harvested in fields that contain sewage are another source of infection. Anything that could potentially contain fecal matter is a source of shigella.

CDC – Shigella

Toxoplasma gondii

Toxoplasma gondii is a protozoan parasite that causes a condition called Toxoplasmosis. One of the methods this parasite is transmitted to humans is through the consumption of raw or undercooked meat. Any items that have come into contact with raw meat that is infected is also a source of transmission. Most often, the disease is asymptomatic; however, some may show signs of malaise and fever. It is most harmful to fetuses and persons who are immune compromised. People who develop toxoplasmosis via the ingestion of raw food make up 50 percent of the toxoplasmosis deaths in the U.S., according to the CDC. To prevent infection via consumption of T. gondii, foods should be cooked so that they reach temperatures that are safe. Washing and peeling vegetables and fruit will also reduce the risk of exposure. Practicing proper hygiene after handling raw poultry, meat, and seafood is also crucial, as is wiping down counter tops, cutting boards, and any utensil or surface that may have come in contact with raw foods.

Preventing Infection with Toxoplasma gondii (PDF)

Vibrio vulnificus

Vibrio vulnificus is a naturally occurring bacterium that occurs in shellfish in salt water in coastal areas. It is found in oysters and clams, and consumption of this bacterium by susceptible persons results in very serious illness and even death. People who are susceptible to illness from V. vulnificus include person who suffer from liver cancer, hepatitis, and other liver disorders; diabetics, people who are immunocompromised – including people undergoing treatment for cancer, and HIV-positive individuals. Once infected by the bacterium via consumption, susceptible individuals may develop gastroenteritis, or primary septicemia. To avoid potential health dangers associated with the consumption of V. vulnificus, people who are at risk should avoid eating raw or undercooked clams or oysters.

Vibrio Vulnificus Fact Sheet (PDF)

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