Class of Pathogen

Species or Type

Basic Biology

Incubation Period

Clinical Picture

Food Items Commonly Involved

Comments

BACTERIA^a

Bacillus cereus

Aerobe; gram-positive, spore-forming bacillus

30 minutes-15 hours

Diarrhea, abdominal cramps, vomiting due to toxemia from heat-stable toxin produced in improperly stored food containing the spores

Meats, milk, vegetables, fish, rice, potatoes, and cheese

This organism can cause emetic toxemia with diarrhea when food with preformed toxin is ingested. It can also cause an infection upon ingestion of a large number of the bacteria which can multiply in the gut and then produce the toxin. Psychrotrophic strains, which can multiply under refrigeration, may end up in powered milk and then grow to harmful levels in infant formulae stored improperly

Campylobacter (C. jejuni causes nearly 80% of campylobacteriosis cases in humans)

Microaerophile; gram-negative, motile, spirals

2-5 days

Nausea, abdominal cramps, diarrhea, and vomiting

Poultry and poultry products, unpasteurized milk and cheeses made from it. Eggs, poultry, raw beef, cake icing

Relatively sensitive to heat and drying. Third leading cause of domestically-acquired bacterial foodborne illness in the U.S. with about 900,000 cases/year. A one-third drop in the number of cases in the past decade due to better food quality and consumer awareness. Guillain-Barré syndrome and miscarriage are rare complications. Those with HIV/AIDS have a 40-fold higher risk of infection

Helicobacter pylori

Microaerophile; gram-negative bacillus

3-7 days

Epigastric pain, nausea, and vomiting

Common as a part of the normal gut flora. Known to cause peptic ulcers and also gastric carcinoma. However, potential for foodborne spread remains ill-defined

Clostridium botulinum

Anaerobe; gram-positive, spore-forming bacillus

12-36 hours

Nausea, vomiting, diarrhea, fatigue, dry mouth, double-vision, paralysis, respiratory failure from toxemia due to a heat-labile neurotoxin toxin

Low-acid canned foods, meats, sausage, fish

Much less common due to better methods of canning food

Clostridium perfringens

Anaerobe; gram-positive, spore-forming bacillus

8-22 hours

Abdominal cramps, diarrhea, and dehydration due to toxemia from a heat-labile enterotoxin

Undercooked meats and gravies

Can also cause wound infections and gas gangrene

Pathogenic Escherichia coli (enterotoxigenic, enteroinvasive, enteropathogenic, enterohemorrhagic, enteroaggregative, and diffusely adherent)

Facultative anaerobe; gram-negative bacillus

8 hours-4 days

The pathogenic types cause damage via heat-labile and heat-resistant toxins, Anemia, hemorrhagic colitis, hemolytic uremic syndrome with kidney failure due to strains such as O157:H7

Ground beef, raw milk

There is an ever-widening spectrum of pathogenic E. coli often involved in serious cases of food- and waterborne infections. A recent example is that of serotype O104:H4 which caused a significant foodborne outbreak in Germany. Some of the strains are associated with traveler’s diarrhea. These agents are also classical examples of how these foodborne infections could lead to long-term damage such as kidney failure

Listeria monocytogenes

Facultative anaerobe; gram-positive bacillus

2-3 weeks

Meningitis, septicemia, miscarriage

Raw vegetables, milk, cheese, meat, seafood

Can grow in refrigerated food. Pregnant women, the aged, and immuno-compromised are at much higher risk of infection with severe outcomes

Salmonella (several typhoidal and non-typhoidal species)

Facultative anaerobe; gram-negative bacilli

12-72 hours

Nausea, diarrhea, abdominal pain, fever, headache, chills, prostration

Meat, poultry, egg or milk products

Over a million cases of domestically-acquired nontyphoidal salmonellosis annually in the U.S. Mortality rate as high as 4% in outbreaks in vulnerable populations

Staphylococcus aureus

Facultative anaerobe; gram-positive coccus

1-6 hours

Severe vomiting, diarrhea, abdominal cramps due to heat-stable enterotoxin from certain strains

Custard- or cream-filled baked goods, ham, poultry, dressings, gravy, eggs, potato salad, creamy sauces, sandwich spreads

A common type of foodborne intoxication. In the U.S., about 250,000 cases and 6 deaths occur each year

Shigella (S. sonnei, S. boydii, S. flexneri, and S. dysenteriae)

Facultative anaerobe; non-motile, gram-negative bacillus

12 hours-3 days

Abdominal pain and severe cramps, fever, vomiting, diarrhea with blood/mucus in stool

Fresh raw vegetables, dairy products, and poultry

Highly infectious toxin-producers. Humans believed to be only hosts.

Rare sequelae include mucosal ulceration, rectal bleeding, reactive arthritis, and hemolytic uremic syndrome. In the U.S., of the annual 375,000, 31% may be foodborne

Vibrio cholerae

6 hours-3 days

Enterotoxin causes severe diarrhea (rice-water stools) and occasional vomiting with potentially fatal dehydration

Shellfish, crab, lobster, shrimp, squid, and finfish

Case-fatality rate of up to 50% if left untreated. Once a major enteric pathogen, it is now rare in the U.S. and Canada with less than 100 foodborne cases annually in the U.S. However, millions of cases of cholera occur each year in developing countries even today and point to the high risk of importations via infected humans and imported food

Vibrio (V. parahaemolyticus and V. vulnificus)

Facultative anaerobe; gram-negative, curved rods

4 hours-4 days

Abdominal cramps, chills, nausea, vomiting, fever, and bloody diarrhea Excrete toxins in infected fish and shellfish

Fish and shellfish

V. parahaemolyticus and V. vulnificus are halophiles (salt-loving), and can infect open wounds exposed to sea water or after injuries from processing sea food. In the U.S. about 45,000 cases of V. parahaemolyticus infection are reported each year, 86% of them foodborne.

V. vulnificus infections may be more severe but are rare in the U.S. and Canada

Yersinia enterocolitica and Y. pseudo-tuberculosis

Facultative anaerobe; gram-negative bacillus

1 day-2 weeks

High fever, stomach pain, diarrhea (stools may have blood), and vomiting

Meats (pork, beef, lamb, etc.), oysters, fish, crabs, and raw milk

Can grow in refrigerated food. Rare sequelae include reactive arthritis. May be misdiagnosed as appendicitis

Brucella abortus