Causes Of Food poisoning
Food poisoning is caused by the contamination of food by either microbes or any other toxins.
A. Microbial contamination
1. Bacteria: It is the most common cause of food poisoning. The symptoms and severity of the infection depend upon the type of bacteria that has contaminated the food. Some of the bacteria that cause food poisoning are:
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Campylobacter: These bacteria usually contaminate raw/undercooked meat, raw milk, and contaminated water. The incubation period (time between exposure of bacteria to the onset of symptoms) is 2-5 days. The symptoms of this infection generally last for a week.
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Salmonella: The contaminated raw/undercooked meat, raw eggs, milk, and other dairy products are the main sources of these bacteria. The symptoms start appearing between 12 to 72 hours.
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Listeria: These bacteria are found in “ready-to-eat” foods such as pre-packed sandwiches, hot dogs, cooked sliced meats, and soft cheeses. The symptoms can appear from a few days to several days. The food poisoning usually resolves within 3 days.
Note of caution: Pregnant women are 10 times more likely than other people to get Listeria infection. It can cause complications such as miscarriage, stillbirth, or premature birth.
Other less common microbes
1. Parasites: Parasites are the organisms that drive their nutritional requirements from other living organisms. The symptoms of food poisoning caused by parasites develop within 10 days of exposure to the parasite. The common examples of parasites that cause food poisoning are:
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Giardia intestinalis
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Cryptosporidium
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Entamoeba histolytica
2. Viruses: The viruses that can cause food poisoning spread through contaminated water. It can also spread via a person infected with the virus while preparing or handling food. The common viruses that cause food poisoning include:
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Rotavirus
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Adenovirus
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Parvovirus
3. Fungi: There are several fungi that may cause food poisoning. Some fungi produce harmful chemicals that contaminate foods. The common examples of fungi that can cause food poisoning are:
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Alternaria
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Aspergillus
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Candida
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Fusarium
B. Non-microbial
In some cases, harmful chemicals are already present in the food which can cause food poisoning. Fish and shellfish may contain toxins produced by algae or bacteria present in water.
Unwashed produce may also cause food poisoning due to the presence of pesticides used during crop production.
The contaminants can be of:
- Vegetable origin (Mushrooms)
- Animal origin (Shellfish)
- Chemicals (Flavouring agent, coloring agent, and preservatives)
How does the food get contaminated?
Food is not only contaminated in the kitchen. It can be exposed to contamination during its production, harvesting, processing, storing, shipping and preparation.
Microbes can cause food poisoning if they are not washed off or killed before consuming. The following things can keep the microbes alive to cause food poisoning:
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Consuming partially cooked food
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Keeping cooked food unrefrigerated for a long period
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Storing packaged food at the wrong temperature
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Promptly refrigerating hot food
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Keeping raw foods such as beef, poultry, and eggs together with ready-to-eat foods
The microbes of food poisoning can also spread through an infected person via:
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Eating food that is touched by the infected person
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Cross-contamination (where harmful bacteria are spread between food, surfaces and equipment)
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Sometimes, food poisoning can also occur through having ready-made contaminated food
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Touching contaminated surfaces and objects such as handrails, elevator buttons, utensils, and doors while eating or handling food
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Sharing food and beverages with the infected person
