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July 4, 2008
Home » Food Safety & Nutrition » Food Safety Resources » Common Pathogens
About Foodborne Illness: Common Pathogens

E. coli 0157:H7
Salmonella
Listeriosis
Hepatitis A
Norwalk Virus
Vibrio vulnificus
Staphylococcal food poisoning
Shigellosis
Clostridium perfringens
Clostridium botulinum
Campylobactor jejuni
Bacillus cereus

  E. coli 0157:H7


Disease Summary

E. coli 0157:H7 is one of the hundreds of strains of E. coli normally found in the large intestine of animals. First recognized in the United States in 1982, E. coli 0157:H7 has been associated with several serious outbreaks in the United States and is most commonly linked to undercooked ground beef.

Symptoms
Symptoms are usually characterized by severe abdominal pain, cramps, nausea, vomiting, diarrhea and occasionally fever. Hemolytic Uremic Syndrome (HUS) is a serious consequence of this disease and is the leading cause of kidney failure in children. Central nervous system disease, seizures, coma and blood clots in the brain may also develop, and may result in death.

Source
Humans and animals. Only humans exhibit symptoms of illness. Mode of Transmission The organism resides in the intestinal tract and is shed in the feces. Slaughter and milking procedures can contaminate food products. While roasts and steaks may become contaminated, the bacteria usually are only found on the exterior of such products, and can be easily killed during the cooking process. However, hamburger and other ground meat products may evenly distribute the bacteria throughout the product. If the product is not thoroughly cooked throughout, some organisms may survive. Illness can occur after ingesting only small amounts of this pathogen. E. coli 0157:H7 has been isolated in raw and undercooked meats, cheeses, lettuce, unpasteurized milk, raw finfish, cream pies, mashed potatoes and other prepared foods.

Control
— Food-protection education
— Cook meats thoroughly, until the juices run clear. (155ºF for ground meats/hamburger)
— Avoid cross-contamination (contact of raw food with cooked foods)
— Good personal hygiene with an emphasis on handwashing

Links
FDA's Bad Bug Book | U.S. Centers for Disease Control

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  Salmonellosis


Disease Summary

Salmonella is an intestinal bacterium that is commonly found on raw meats, poultry and in eggs, or in foods containing raw or undercooked milk or egg products. There are hundreds of Salmonella serotypes, and S. typhimurium and S. enteritidis are the most common. Salmonella bacteria can be killed by temperatures of 130ºF or higher for 2 hours, or at 165ºF for a few seconds. A person with Salmonellosis can transmit the disease to others for up to several days to several months via cross-contamination and inadequate handwashing after toilet use.

Symptoms
Salmonellosis is usually characterized by headache, abdominal pain, diarrhea, nausea, vomiting, dehydration, fever and loss of appetite. Symptoms of Salmonellosis commonly appear within 6-72 hours after the ingestion of the organism and may persist for as long as 2-3 days. Death is uncommon, except for the very young, very old and the immuno-compromised.

Source
Humans and domestic or wild animals: poultry/eggs, swine, cattle and rodents, and pets such as turtles, chicks, dogs and cats. Humans can be carriers (have and transmit the disease without showing symptoms) and shed the disease in the feces for up to one year.

Mode of Transmission
Ingestion of fecal material containing the bacteria via undercooked meats or eggs, contaminated food or tableware, and untreated public water supplies.

Control
— Food-protection education
— Good personal hygiene and handwashing
— Proper cooking temperatures
— Proper cleaning/sanitizing of food equipment
— Exclusion of sick employees

FDA's Bad Bug Book
CDC and CDC

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  Listeriosis

Disease Summary
Listeriosis is a bacterial illness. Listeria is frequently found in soil, water and plant matter; and it has the ability to survive and grow in moist, cool locations such as refrigerators. Listeria is a common bacteria and is very difficult to eliminate. However, thorough cooking will destroy it. Listeriosis can be a severe illness for the old, very young and for people who are immuno-compromised.

Symptoms
The infection is usually characterized by nausea, vomiting, headaches, delirium, coma, collapse, shock and lesions on vital organs. In pregnant women, the illness can cause a miscarriage or result in stillbirths. Listeriosis may also cause severe retardation, meningitis and death in newborns.

Source
Infected wild and domestic mammals and fowl are the most likely sources for Listeriosis. The organism is frequently found in soil, water and plant matter that animals ingest and excrete, allowing further transmission.

Mode of Transmission
When people become infected with Listeriosis, they may excrete the bacteria in their feces; thus handwashing is extremely important. Improper sanitation of refrigerators may increase spread of Listeriosis. Cheese made with unpasteurized milk may support the growth of Listeria during ripening and has been implicated in serious outbreaks.

Control
— Food-protection education
— Good personal hygiene and handwashing
— Keep facilities dry -- Listeria can grow on wet floors, in drains, in ceiling condensates and on sponges
— Proper cleaning/sanitizing of equipment
— Washing vegetables/produce
— Avoiding contact between raw and cooked foods

FDA's Bad Bug Book | U.S. Centers for Disease Control

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  Hepatitis A


Disease Summary

Hepatitis A virus is a communicable disease that may be foodborne, but is also transmitted through person-to- person contact in settings such as daycare centers and hospitals by persons who do not adequately wash their hands after rest room use, and by consumption of raw or undercooked shellfish harvested from contaminated waters. In the foodservice industry, the primary controls for Hepatitis A are proper training and effective supervision of employees to ensure good hygienic practices, proper handwashing and safe handling of food and tableware.

Symptoms
Abrupt fever, fatigue, loss of appetite, nausea, abdominal discomfort, jaundice, dark urine and joint aches. Symptoms of this infection usually occur within 15-50 days following exposure. The greatest risk of illness transmission from an infected person is one week before until one week after symptoms first appear. Source Humans; occasionally nonhuman primates.

Mode of Transmission
Person-to-person via fecal-oral. Common source outbreaks have been related to contaminated water; food contaminated by infected foodhandlers, especially food that is not cooked after handling; and raw or undercooked shellfish from contaminated waters.

Control
— Food-protection education
— Minimize manual contact with food and food contact surfaces
— Good personal hygiene and handwashing
— Approved food sources
— Proper food cooking temperatures
— Vaccines for active immunization; limited use (available as of 1995)
— Exclude infected employees

FDA's Bad Bug Book

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  Norwalk Virus

Disease Summary
Norwalk virus is usually associated with poor personal hygiene and contaminated soils or water. Because Norwalk is a virus, it does not grow or reproduce in food. However, when food is contaminated with the virus via hands, soil or water, it is not easily killed by cooking. Because viruses cannot be isolated readily or detected in contaminated food, preventive controls are extremely important.

Symptoms
Norwalk virus is characterized by nausea, vomiting, diarrhea, abdominal pain, headache and low-grade fever. Symptoms usually appear 24-48 hours after infection, and may persist for as long as 1-2 days.

Source
Man is the only known source of the virus. The virus is found in the feces of an infected person and is shed in human waste.

Mode of Transmission
Poor personal hygiene/lack of handwashing after toilet use and consumption of contaminated water supplies are the most common mode of transmission. Raw shellfish harvested from contaminated waters, contaminated ready-to-eat foods, eggs and even ice have caused Norwalk virus outbreaks.

Control
— Food-protection education
— Good personal hygiene and handwashing
— Food and water from reputable sources
— Washing raw vegetables

FDA's Bad Bug Book

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  Vibrio Vulnificus


Disease Summary
Vibrio vulnificus is a common, naturally occurring bacterium that is present in coastal waters throughout the world. It is not the result of pollution and can be higher in concentration during the warmer months. The U.S. Food and Drug Administration estimates that 5-10% of all shellfish are contaminated with Vibrio vulnificus. Currently, there are no practical methods available to eliminate Vibrio vulnificus from coastal waters or from shellfish harvested from these waters. Most healthy adults are not at risk for Vibrio vulnificus illness and may not experience any symptoms or illness. However, the illness can be very severe in immuno- compromised individuals such as the young, the elderly and persons with liver disease.

Symptoms
The infection is usually characterized by fever, chills, nausea, vomiting, diarrhea, shock, abdominal pain and severe fatigue. Localized skin or blood infections may occur, which may then progress to sores or ulcers. Onset of symptoms is rapid, usually occurring within 3 days after ingestion of the bacteria. Immuno-compromised persons are at an increased risk for acquiring Vibrio vulnificus, and the infection can cause severe illness with a high mortality rate in those persons.

Source
Warm coastal waters, most commonly around the Gulf of Mexico, but the organisms have also been found in water samples from both the Atlantic and Pacific coasts and from other locations worldwide.

Mode of Transmission
Vibrio vulnificus is transmitted to humans through consumption of improperly cooked or raw shellfish harvested from infected waters, or through open wounds in contact with seawater.

Control
— Food-protection education
— Avoid exposure of recent or healing skin abrasions to seawater
— Immuno-compromised persons should avoid consumption of raw or undercooked shellfish and ensure the shellfish is thoroughly cooked
— Proper cleaning/sanitizing equipment to avoid cross- contamination of raw shellfish and cooked foods
— Good personal hygiene with an emphasis on handwashing
— Using shellfish from approved sources; however, individual shellfish cannot be tested for V. vulnificus, so "approved sources" do not guarantee risk free.

FDA's Bad Bug Book

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  Staphylococcal Food Poisoning

Disease Summary
Staphylococcal food poisoning is one of the most commonly reported illnesses in the United States. Staphylococcal poisoning is an intoxication; it is caused by toxins that are produced by the staph. bacteria. When a person consumes food that is contaminated with staph. toxins, that person becomes ill from the toxin, not the bacteria. Deaths are rare and the duration of the illness usually lasts only one or two days. However, sometimes the intensity and severity of the symptoms require hospitalization.

Symptoms
Staphylococcal food poisoning is usually characterized by nausea, vomiting, diarrhea, dehydration, prostration, cramps, subnormal temperatures and lowered blood pressure. Symptoms appear within 30 minutes to 7 hours (2-4 hours is most common) after eating the contaminated food, and may last for up to 24-48 hours.

Source
Humans are the most common source, but cows, dogs and fowl also can be a source. It is estimated that 40-50% of healthy adults carry staph. bacteria in nasal passages, throat, hands and skin. These bacteria also are found in infected cuts, boils, burns, abrasions and pimples.

Mode of Transmission
By ingestion of a food product contaminated with the toxin produced by the staph. bacteria. Contaminated ready-to-eat, high-protein foods such as meat, poultry and dairy products subjected to temperature abuse are the most common source of this illness.

Control
— Food-protection education
— Good personal hygiene with an emphasis on handwashing and minimal food handling
— Food stored at proper temperatures.
— Cool potentially hazardous foods to 41ºF within 6 hours (145ºF-70ºF in 2 hours and 70ºF-41ºF in an additional 4 hours.)
— Potentially hazardous foods at room temperature should be discarded after 4 hours
— Temporary exclusion of food handlers with cuts, abrasions, pimples, boils or upper respiratory symptoms

FDA's Bad Bug Book

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  Shigellosis


Disease Summary

Shigellosis is a bacterial infection that is commonly referred to as dysentery. Implicated foods include contaminated raw produce and moist ready-to-eat foods such as potato, tuna, turkey and macaroni salads that have been mishandled during preparation by an infected person. Contaminated water has also been identified as a source of this illness.

Symptoms
This illness is usually characterized by diarrhea, cramps and chills, often accompanied by fever. Symptoms usually appear within 12-96 hours, but can take as long as one week. Duration of illness is usually 4-7 days.

Source
Humans are the most significant source. People may carry this pathogen for several weeks and excrete it in their feces. Asymptomatic carriers may transmit the illness to others for months, or longer.

Mode of Transmission
Illness can occur after ingesting as few as 10-100 individual bacteria. The bacteria are usually spread by persons with poor handwashing habits after toilet use, who subsequently contaminate food. Flies have also been known to transfer the disease from feces to water, milk and food.

Control
— Food-protection education
— Good personal hygiene and handwashing
— Fly control
— Remove employees with the illness from food handling duties until cleared by a physician

FDA's Bad Bug Book

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  Clostridium perfringens

Disease Summary
Clostridium perfringens is widely distributed in the environment and frequently occurs in the intestines of humans and many domestic and feral animals. Spores of the organism persist in soil, sediments, and areas subject to human and animal fecal pollution.

Symptoms
Clostridium perfringens can cause diarrhea and gas pains about 8 to 24 hours after eating. The illness usually lasts 1 day, but some symptoms may last 1 to 2 weeks for the elderly or very young.

Source
The bacteria can be found in soil, dust, sewage, and intestinal tracts of animals and humans. The organism grows in little or no oxygen.

Mode of Transmission
Clostridium perfringens bacteria are capable of producing a food-poisoning toxin that can be produced in foods that have experienced temperature abuse. Cooking can destroy the bacteria, but some toxin-producing spores may survive.

Control
Cool foods rapidly in small quantities. Avoid preparing foods hours in advance. Reheat foods rapidly to a minimum of 165° F. Proper cleaning and sanitizing of equipment. Avoid using leftovers.

FDA's Bad Bug Book

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  Clostridium botulinum

Disease Summary
Clostridium botulinum is an anaerobic, gram-positive, spore- forming rod that produces a toxin. The spores are heat resistant and can survive in foods that are incorrectly or minimally processed. Foodborne botulism is a severe type of food poisoning caused by the ingestion of foods containing the potent toxin formed during the growth of the organism.

Symptoms
Onset of symptoms is usually 2 to 36 hours after ingestion of food that contained the toxin, but sometimes appear as few as 2 hours or as long as 8 days after eating. Signs are double vision, droopy eyelids, trouble speaking and swallowing, difficulty breathing and paralysis. It is often fatal.

Source
The organism and its spores are widely distributed in nature. They occur in both cultivated and forest soils, bottom sediments of streams, coastal waters, and in the intestinal tracts of fish and mammal, and in the gills and viscera of crabs and other shellfish.

Mode of Transmission
Bacteria produce a toxin that causes the illness. Clostridium botulinum has been demonstrated in a variety of foods such as canned corn, peppers, green beans, soups, smoked fish, improperly canned foods, garlic in oil, vacuum - packaged and tightly wrapped foods.

Control
— Use only commercially canned or smoked products.
— Refrigerate olive oil and garlic.
— Discard bulging canned goods.
— Refrigerate foods.
— Rapidly chill in small quantities.

FDA's Bad Bug Book

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  Campylobactor jejuni


Disease Summary
Camplobacter jejuni is a microaerophilic organism, which means it has a requirement for reduced amount of oxygen. Surveys have shown that Campylobacter is the leading cause of bacterial diarrheal illness in the United States. It causes more disease than Shigella or Salmonella combined.

Symptoms
Initial symptoms include fever, headache, and muscle pain followed by diarrhea, abdominal pain, and nausea. These symptoms may appear 2 to 5 days after eating and may last up to 7 to 10 days.

Mode of Transmission
Camplobacter can be transmitted by contaminated water, raw milk, and raw and undercooked meat, poultry or shellfish

Source
Healthy chicken carry this bacteria in their intestinal tracts sometimes causing the contamination of raw poultry. Raw milk can also be a source; the bacteria are carried by healthy cattle and by flies on farms. Non - chlorinated water may also be a source for the infection. However, properly cooking chicken, pasteurizing milk, and chlorinating drinking water will kill the bacteria.

Control
— Avoid cross- contamination of foods.
— Cook foods thoroughly.
— Practice good personal hygiene.
— Only consume pasteurized milk products.

FDA's Bad Bug Book | U.S. Centers for Disease Control

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  Bacillus cereus


Disease summary

Bacillus cereus food poisoning is the general description, although two recognized types of illness are caused by two distinct metabolites. A large molecular weight portion causes the diarrheal type of illness, while the vomiting type of illness is believed to be caused by a heat stable peptide.

Symptoms
The symptoms of bacillus diarrheal type mimic those of clostridium perfringens. The onset of watery diarrhea, abdominal cramps, and pain occurs 6 - 15 hours after consumption of contaminated food. Nausea may accompany diarrhea, but vomiting rarely occurs. Symptoms last for 24 hours. The emetic type is characterized by nausea and vomiting within 0.5 - 6 hours after consumption of contaminated foods. Occasionally, abdominal cramps and/or diarrhea may also occur. These symptoms last less than 24 hours.

Source
A wide variety of foods including meats, milk, vegetables, and fish have been associated with the diarrheal type. The vomiting - type are associated with rice products, and other starchy foods such as pastas, potato, and cheese products.

Modes of Transmission
— Ingestion of foods noted above that has been abused by temperature is the main way to transmit the bacteria.
— Employees handling foods who demonstrate poor personal hygiene practices can also transmit the bacteria fecal to oral to the customer.

Control
— Practice proper handwashing.
— Rapidly cool foods.
— Cool foods in small quantities.
— Wash foods prior to preparation.

FDA's Bad Bug Book

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