Food Poisoning Bacteria & Viruses – Symptoms, Treatment & Prevention
There are lots of different types of food poisoning bacteria and viruses that can make us ill when we eat or come in to contact with contaminated food. In this guide our experts look at thirteen of the most common bugs that can cause food poisoning. We look at what foods they commonly affect, typical symptoms, what to do if you become infected and proactive tips on preventing contamination.
Can bacteria and viruses cause food poisoning?
Most food poisoning cases are caused by either bacteria or viruses that have contaminated food and are then consumed allowing bugs to enter and infect the body.
Most cases of food poisoning can be prevented with propper cleaning, separating, cooking and chilling procedures
The type of bacteria or virus present in the food that is eaten will determine your symptoms, and how severe they are.
We can prevent many cases of food poisoning by following the basic regime of cleaning, separating, cooking and chilling.
What are the most common types of food poisoning bacteria and viruses?
Some of the most common types of bacteria and viruses causing serious illness are listed below, along with tips on how to prevent food contamination and so keep you and others safe from harm.
Bacillus cereus
Bacillus Cereus is a type of contamination caused by spores, which can grow in leftover rice which is stored for too long at room temperature.
If you have food poisoning caused by bacillus cereus, you can expect around 24 hours of vomiting and diarrhoea, which often comes on within 30 minutes of eating the contaminated food.
Try to drink lots of water and rest, but if you think you are becoming dehydrated, call your GP or NHS Direct for advice.
The best way to prevent illness caused by bacillus cereus is to ensure foods are cooked properly.
If you have leftovers, cool them quickly in a shallow layer, put them in to a clean, airtight container and put them straight into the fridge.
Botulism
Fortunately botulism is a very rare, but dangerous type of food poisoning bacteria.
Botulism infection is often caused by eating food which hasn’t been canned or preserved properly.
It can also be found in soil, and in other foods such as cream-filled pastries or custard.
Young children can also pick up botulism from honey.
There is a range of symptoms associated with this illness.
Very young children or babies may appear weak, lethargic and “floppy”.
Older patients may suffer eyesight problems, slurred speech and have difficulty in swallowing.
If you suspect botulism in yourself or a family member, you should go to A&E immediately as this is not an illness you can manage yourself at home.
You can reduce your risk of botulism by avoiding eating from cans which are broken, damaged or bulging, and by not giving honey to babies under 12 months of age.
Campylobacter food poisoning
Most cases of campylobacter related food poisoning are picked up from raw chicken or turkey.
It may also be present in shellfish, milk which has not been pasteurised, or untreated water from streams or lakes.
This type of food poisoning can cause high temperatures, vomiting and diarrhoea, which may contain blood.
The illness can last from 2 up to 10 days, and you can usually treat yourself at home by maintaining fluid levels and plenty of rest.
The good news about campylobacter is that it is a bacterium that is very easy to kill.
To be safe, always cook food through until piping hot in the middle.
Avoid cross contamination; by for example using the same chopping board for salad and raw chicken.
Don’t drink unpasteurised milk, and take water purification tablets when camping rather than drinking out of a lake or stream.
Clostridium perfringens
In the UK clostridium perfringens is one of the most common types of food poisoning bacteria, which is thought to be responsible for as many as a million cases each year.
The foods most commonly associated with clostridium perfringens are beef, poultry and gravy.
If you are affected by this type of food poisoning bacteria you will vomit, have abdominal pains and suffer from diarrhoea.
Bacteria such as clostridium perfringens can be killed by ensuring all food is well heated to at least 82 centigrade throughout.
If you are cooking food to use at a later date, chill it quickly and refrigerate or freeze as soon as possible.
Cronobacter sakazakii
Cronobacter sakazakii is a bacterium that is very rare, but can cause serious or fatal damage to the central nervous system.
Most cases associated with cronobacter are contracted from baby formula milk.
Symptoms include jaundice, fever, constant crying or lethargy.
Any baby showing these symptoms should receive medical attention immediately.
Avoid cronobacter infections by always following manufacturer’s instructions when making up formula milk.
Hot water at 70oC or more should always be used when making up bottles… and never keep bottles for more than 24 hours after making them up.
Escherichia coli (E. coli)
E.coli bacteria is found in a wide range of different foods, from unpasteurised milk and cheese to bagged salads and contaminated water.
Once a person is infected by this bug, they can pass it to others through faecal contamination.
E. coli causes very severe abdominal pain, diarrhoea and vomiting.
In most cases, infected people start to feel better after a week.
Otherwise healthy adults can treat the infection at home by drinking water and taking plenty of rest.
However, very young children or adults with existing health conditions may need hospital treatment.
Avoid picking up E. coli in the first place by practicing good food hygiene.
Always ensure minced beef products such as burgers are cooked through.
Avoid unpasteurised milk and cheese products.
As this bacteria is carried by many farm animals, ensure that everyone washes their hands thoroughly after contact with sheep, goats or cows.
Hepatitis A
Hepatitis A contracted from food is very uncommon in the UK.
However, it is something which you need to be aware of when travelling to warmer parts of the world.
If you are travelling to areas where Hepatitis A is a problem, then speak to the nurse at your GP practice about immunisations.
Hepatitis A can be transmitted through sewage and untreated water, and can be picked up from shellfish, any raw food such as salad or from food handlers with poor hygiene.
Listeria
Listeria is a rare form of food poisoning bacteria which can be picked up from products made using unpasteurised milk, from soft cheese such as brie or camembert, or from chilled deli products such as sliced meats or pate.
Listeria infection causes listeriosis, a serious illness which can cause high temperatures, muscle aches, confusion or loss of balance.
It’s particularly serious in pregnant women, as listeriosis can cause premature labour and death in unborn babies.
Antibiotics can be used to treat listeriosis, but to be successful they must be administered quickly.
Pregnant women in the UK are routinely advised to avoid soft cheeses and pate to reduce the risk of listeria.
Everybody should avoid raw or unpasteurised milk, and any cheeses or other products made from it.
Norovirus
Also known as the “winter vomiting bug”, norovirus can cause serious nausea, vomiting and diarrhoea and is highly infectious.
Although norovirus can be spread by food, it’s more likely that you pick it up from contaminated surfaces such as door handles, hand rails etc,, or from someone else who is affected.
However, if infected food workers touch ready to eat foods such as sandwiches or salads the infection can also be transferred in this way.
If you contract norovirus, you should start to feel better after 2 or 3 days.
Drink as much water as you can to stay hydrated, and take plenty of rest.
The best way to prevent norovirus is being strict about handwashing.
Always wash your hands after using the bathroom, before preparing food and before eating.
People who have sickness or diarrhoea should not prepare food.
Wash kitchen surfaces down with a bleach based cleaner to prevent further infection from spreading.
Salmonella
Salmonella is most commonly associated with chicken, eggs and poultry but can also be found in vegetables, fruit and nuts.
Salmonella can also be contracted from contact with reptiles and amphibians.
If you contract salmonella, you can expect the typical food poisoning symptoms of vomiting and diarrhoea, lasting between four days and a week.
Salmonella is particularly dangerous for small children, or the elderly, and in serious cases, hospital treatment might be required.
Avoid salmonella by making sure that all eggs, chicken and poultry products are cooked through.
Take care not to use the same chopping board for raw chicken, then other products.
If you keep reptiles or amphibians as pets, get into the habit of thoroughly washing your hands with soap and hot water after handling them or cleaning out their tank.
Shigella
Shigella is also known as dysentery, and is typically associated with overseas travel rather than being picked up in the UK.
It causes stomach cramps, high temperatures, nausea and diarrhoea.
Treat a shigella infection be taking extra care over handwashing, and drink plenty of fluids.
If you are lucky enough to be on holiday overseas, try to stick to hot cooked foods rather than salads and fruit.
Avoid ice in drinks, and only drink unopened or sealed bottled water rather than straight from the tap.
Staphylococcus aureus
Staphylococcus aureus is a type of food poisoning sometimes known as “staph”.
People who are infected with the bug can transfer it to food if they don’t wash their hands properly and then touch food designed to be eaten straight away, such as puddings or sandwiches.
This type of infection can cause sickness very quickly, within as little as 30 minutes.
Sufferers will experience abdominal cramps, nausea and vomiting.
The good news is that most people recover with 24 hours, aided by fluids and rest.
You can help prevent staph infections by cooking food through to piping hot.
Use a thermometer if you are unsure of the temperature and refrigerate any leftovers promptly.
Always wash your hands before preparing food and don’t prepare food for others if you are ill with vomiting or nausea.
Vibriosis
If you’ve ever been ill after eating raw oysters, then it was probably either norovirus or vibriosis which was to blame.
Vibrio bacteria causes the classic food poisoning symptoms of nausea, pain and diarrhoea and can last for around three days.
It’s very easy to avoid this type of infection, as the vibrio bacteria are killed by cooking.
Never eat raw shellfish and make sure anything you cook is piping hot throughout.
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