Food bacteria: what they are and how to defend yourself

Food bacteria: what they are and how to defend yourself

Every year there are many people who fall ill due to food-borne pathogens, i.e. viruses , parasites , toxins and harmful bacteria present in foods which, if ingested, trigger more or less serious disturbances.

These elements enter food in different ways. The water used to irrigate the soil where vegetables and fruit are grown, for example, can be contaminated with unwanted germs which are then transferred to them. In other cases, pathogens can be found on the skin of farm animals and subsequently penetrate meat and poultry products during slaughter and processing; or be picked up by fish that eat smaller organisms in the sea.

Finally, people infected with a foodborne illness who handle or prepare food for others can also transfer germs unintentionally.

Most bacteria require certain conditions to thrive . Hot, moist, or slightly acidic foods are more prone to bacterial growth.

Even if most of the time food-borne illnesses are cured without any medical intervention, it is useful to recognize the signs that can reveal their presence in order to be able to prevent them in some cases.

Most common foodborne pathogens

  • Noroviruses
  • Salmonella
  • Clostridium Perfringens
  • Campylobacteria
  • Escherichia Coli
  • Listeria
  • Staphylococcus aureus


Virus often listed as the most common cause of gastrointestinal upset. There are various forms of contagion , among which contact with infected people and surfaces, the intake of contaminated food or drink, fresh or ready-made food, crustaceans , sandwiches and cut fruit stand out .

The incubation of the malaise derived from his attack lasts about 12 to 48 hours and the symptoms are diarrhea , vomiting , abdominal pain and nausea.

To reduce the risk, always wash your hands thoroughly with soap and warm water , wear gloves whenever you prepare ready-to-eat foods, and regularly disinfect any surfaces contaminated by the virus.


Bacteria that can be contracted from animal proteins such as poultry, pork , eggs and red meat , but also from fruit, vegetables, sprouts and nuts .

‌The incubation period can last from 6 hours to 6 days and the symptoms are diarrhea, nausea, vomiting, fever and abdominal pain or cramps .

To reduce the risk avoid undercooked proteins such as raw eggs and rare meats and unpasteurized milk .

Clostridium Perfringens

This name indicates toxins produced by some bacteria that cannot be transmitted from person to person but reach the human body through animal proteins such as red meat, poultry or any food left at dangerous temperatures for more than 2 hours.

Incubation lasts from 6 to 24 hours and the symptoms are diarrhoea, vomiting and abdominal pain or cramps .

To reduce the risk ensure that potentially hazardous foods are cooked, reheated or held at safe temperatures. For hot ones it is better to exceed 60°, while for cold ones below 4°.


‌Also known as campylobacteriosis, this infectious microorganism is found in unpasteurized milk and poultry, shellfish and water.

Incubation lasts about 2 to 5 days and the symptoms are diarrhoea, often containing blood, abdominal pain , cramps, fever and vomiting.

To reduce the risk, drink only pasteurized milk and filtered and disinfected water .

Escherichia Coli

The presence of Escherichia Coli in the intestine is completely normal and most of these microorganisms do not induce disease, but some specific ‌forms or subtypes are pathogenic.

These are found in undercooked animal proteins such as raw meat , unpasteurized milk and cheese , raw fruits and vegetables, and contaminated water . Accidental ingestion of feces particles from infected animals or people can also spread Escherichia coli germs.

Incubation lasts 1 to 10 days and symptoms are diarrhoea, often bloody, abdominal pain and vomiting.

Severe Escherichia coli infections can lead to a condition called haemolytic uraemic syndrome , which is characterized by decreased urination , dark colored urine , and pale skin . If one or more of these symptoms occur, contact a doctor.

To reduce your risk, always wash your hands when preparing food and don’t eat high-risk foods.


Listeria is a bacteria that can be found in unpasteurized milk and cheese, raw fruits and vegetables, processed animal proteins such as those in cured meats and smoked fish products such as salmon .

Incubation lasts from 7 to 70 days and the most common symptoms are diarrhea and fever but the bacteria can cause systemic symptoms if they travel beyond the gastrointestinal tract. This condition, called invasive listeriosis , can lead to fatigue, muscle stiffness , confusion and balance problems.

Staphylococcus aureus

Staphylococcus aureus often lives on the skin, so food that has been handled or prepared by anyone with staph is a possible source of contamination. Foods that are not reheated after preparation such as cold cuts, sandwiches, salads and some desserts can also be high-risk sources.

These bacteria produce ‌toxins so the symptoms, which are sudden nausea and vomiting , diarrhea and abdominal pain or cramps , occur rapidly and often within 30 minutes to 8 hours.

To reduce risk, always store food at safe temperatures, avoid preparing or handling food if you experience gastrointestinal symptoms, and wash your hands well and often.



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