What are the Bacteria that cause Food Poisoning?

Food poisoning is a food-borne illness that generally affects the digestive system of an organism. It is commonly caused by viruses and bacteria found in food. However, swallowing bacteria from food does not instantly damage the digestive system. There is a delay between the actual poisoning and the time that the food was eaten. This delay, time before symptoms begin, is called the incubation period of the bacteria. For how long the incubation period lasts, may be hours or days, mainly depends on the type of bacteria and the number of bacteria taken in. So what are the bacteria that cause food poisoning?

Commonly, these kinds of bacteria cause food poisoning: Clostridium perfringens, Listeria, Staphylococci, Salmonella, Campylobacter, and Escherichia coli (E. coli). With warmth and moisture, these bacteria are able to grow within our digestive tract. Through asexual reproduction (division of self), they are able to grow their number exponentially; a single bacterium may end up becoming several million in just 8 hours and multiply to thousands of millions within 12 hours.

Clostridium Perfringens

Clostridium perfringens are often found in low numbers in poultry, raw meat, unpasteurized dairy products, eggs and/or vegetables and crops that have come in contact with soil. This kind of bacteria may also be found in the intestines and manures of other animals and humans, and even in the sewage.

Once infected with Clostridium perfringens, symptoms such as diarrhea and severe abdominal p ain begin to appear. Infection with these bacteria also causes, though occasionally, a bit of nausea.

Foods that are most likely infected with Clostridium perfringens are those cooked slowly in great numbers and are left to stand at room temperature. Clostridium perfringens yields heat-resistant spores, making this type of bacteria almost improbable to be completely eradicated by normal cooking. The spores that are able to survive the cooking temperature may also be prompted to germinate by the heat. So to have greater chances of killing the bacteria, the food must be reheated under a temperature of at least 60°C or preferably 75°C.

Listeria monocytogenes

Listeria monocytogenes can be found in our surroundings. And certain foods like cold cut meats, unpasteurized milk, mould-ripened cheese and pâtés are not left out by this kind of bacteria. In fact, in this food, Listeria is present in a rather great number.

Infection with this kind of bacteria usually affects the elderly, pregnant women and their babies, and other people who have reduced immunity. This infection, or Listeriosis, usually has symptoms of nausea and vomiting. And from Listeria, some infected individuals may also develop meningitis.

Staphylococcus aureus

Staphylococci normally occur in the nose, throat and skin of a human. These are the type of bacteria that is normally transmitted to food through handling. Infection with these bacteria causes nausea, dizziness, abdominal cramping, and severe vomiting. These symptoms are produced by toxins from Staphylococci found in salads (i.e. potato, egg, macaroni, and tuna), pies and cream-filled cakes. These foods are contaminated when not properly handled and chilled.


Salmonella is found in poultry, meat, and dairy products such as unpasteurized milk and eggs. Unless these foods are properly cooked and chilled, salmonella can easily grow and multiply in numbers. Once infected, symptoms such as cramps, nausea, diarrhea, headache, and vomiting are experienced. Infection with this type of bacteria may be worse and pose a life-threatening illness for people with reduced immunity, especially those with HIV/AIDS and/or cancer.

The people infected with salmonella must be particular with their personal hygiene since they pass the bacteria to another person that they come in contact with. For example, if a person infected with salmonella does not properly wash hands after visiting the toilet, then it is very probable that he/she has bacteria on his/her hands. The bacteria on the hands may be easily transferred to the next person that he/she shakes hand with.


Campylobacter is identified as the most common cause of food-borne bacterial infection. It is generally found in poultry, red meat, raw milk and untreated or contaminated water. Even though this type of bacteria does not grow in food, it easily spreads and multiplies. Infection with this type of bacteria shows symptoms of fever, headache and muscle aches, and watery diarrhea that could be severe and bloody case.

Escherichia coli (E. coli)

Most strains of Escherichia coli are found to be harmless. However, there is a particular E. coli strain (0157) that causes severe diarrhea and possible kidney damage. The 0157 strain actually produces a potent toxin that affects not just the kidney but also the renal tract. In some cases, kidney damage and renal failure lead to death. This E. coli, including the 0157 strain, is carried by cattle around 10 to 15 percent of ruminants. These ruminants (cattle, goats, sheep, and deer) provide food to humans and possibly transmit the bacteria through raw or undercooked meat (particularly hamburger) and unpasteurized milk.

These are the bacteria that most commonly cause food poisoning.

One Response to “What are the Bacteria that cause Food Poisoning?”

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  1. Jennet Bryan says:

    Fantastc information on common bacteria found in our food. Clear and concise as my first essay for my Foundation degree in health and social care requires. Thankyou!!

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