Foodborne illness pathogens

Most foodborne illness is caused by pathogenic bacteria or viruses in food.

Other less common foodborne illness occurs from accidental chemical poisoning and natural contaminants.

The most common types of foodborne illness are:

1. bacterial eg Salmonella, Campylobacter, E.coli and Listeria
2. viral eg Norovirus, Rotavirus and Hepatitis A
3. intoxication caused by toxins produced by pathogens such as Staphylococcus aureus, Bacillus cereus and Clostridium perfringens.

Symptoms and the most frequent food vehicle will vary depending on the type of pathogen.

(Wide table: scroll/swipe sideways if not all columns are displayed.)

Pathogen	Microscopic image of pathogen **	Typical incubation period (time between eating and onset of symptoms)	Typical symptoms	Typical food vehicles *
Bacillus cereus toxin (vomiting and diarrhoea)		1 - 6 hours 6 - 24 hours	Sudden onset of severe nausea and vomiting Abdominal cramps, nausea and watery diarrhoea	Improperly refrigerated cooked rice and pasta, and fresh noodles Meats, stews, gravy
Campylobacter		2 - 5 days	Fever, nausea, abdominal cramps and diarrhoea (sometimes bloody)	Raw and undercooked poultry, unpasteurised milk and contaminated water
Clostridium perfringens toxin		6 - 24 hours	Abdominal cramps, watery diarrhoea and nausea	Meats, poultry, gravy, dried or precooked foods
Escherichia coli including (STEC)		2 - 10 days more commonly 3 - 4 days	Diarrhoea (often bloody), abdominal cramps	Improperly cooked beef, unpasteurised milk and juice, sprouts and contaminated water
Hepatitis A		2 - 7 weeks	Jaundice, fatigue, loss of appetite, nausea	Raw or poorly cooked seafood harvested from contaminated waters, ready-to-eat foods handled by an infected food handler
Listeria monocytogenes		3 days - 10 weeks	Meningitis, sepsis, fever	Soft cheeses, unpasteurised milk, ready-to-eat deli meats
Norovirus		24 - 48 hours	Fever, nausea, vomiting, abdominal cramps, diarrhoea and headache	Poorly cooked shellfish, ready-to-eat foods touched by an infected worker
Salmonella		6 – 72 hours, usually 12-36 hours	Headache, fever, abdominal cramps, diarrhoea, vomiting and nausea	Undercooked poultry, raw egg desserts and mayonnaise, sprouts, tahini
Staphylococcus aureus toxin		0.5 – 8 hours	Sudden onset of vomiting and abdominal cramps	Cream desserts and pastries, potato salad
Vibrio parahaemolyticus		4–30 hours, usually 12-24 hours	Nausea, vomiting, abdominal cramps and watery diarrhoea	Undercooked or raw seafood.

*The foods shown in the table have previously been found to be the source of the pathogens listed. This does not mean that these foods are always unsafe to eat  that such pathogens are always present, or that only these foods can carry the pathogen.

**Image credits: Partnership for Food Safety Education (USA); Laboratory of Clinical and Epidemiological Virology, Catholic University of Leuven (Belgium); HealthNJ, Univesity of Medicine and Dentistry of New Jersey (USA).