What is food poisoning?
Food poisoning, medically known as foodborne illness, is a disease caused by the consumption of contaminated (spoiled) food. This can lead to an infection which can be mild or severe, depending on individual factors such as the health of the person, the type of food eaten, and how much was eaten. Most people affected will experience vomiting and/or diarrhea, as well as weakness and fever. It can take a couple of hours to a few days after contaminant exposure to start getting symptoms – this period of time is called the incubation time.
What causes food poisoning?
Food can be spoiled by a wide range of pathogenic (disease-causing) organisms, including bacteria (e.g. salmonella, E. coli), viruses (e.g. norovirus), and certain food-borne parasites. Food poisoning can also be caused by toxins naturally present in the food product, as is the case with certain mushrooms and beans. In recent times, food poisoning has also been attributed to chemicals artificially added to the food, such as pesticides and medicines are given to plants and animals. Food is contaminated due to a variety of factors, including inadequate handling, storage, and preparation of the food. Poor hygiene, food safety, and public health regulation lead to an increased risk of food poisoning.
How to prevent food poisoning?
- Avoid eating food that is past its expiry date
- Cook food thoroughly and to the right temperature, especially meat. You can use a thermometer to guide you through this (e.g. cook poultry to at least 73.8°C, fish to at least 62.7°C and beef to at least 71°C)
- If reheating already cooked food, ensure food is fully heated before eating
- Store food at the right temperature (e.g. chilled foods below 5°C)
- Don’t leave cooked food for prolonged periods of time at warm temperatures
- Wash hands thoroughly before food preparation and before eating
- Someone that is ill or infected should not be preparing the food
- Wash cooking utensils that have made contact with raw eggs, fish, poultry, and meat thoroughly
- Avoiding eating wild mushrooms (unless with professional advice)
- If traveling to a different country, only drink bottled water, or water which you know has been treated. If eating raw vegetables/fruits, only eat ones which can be peeled (e.g. bananas). Eat only hot and freshly cooked food.
Food poisoning symptoms
Food poisoning symptoms differ depending on the type of contaminated food you’ve eaten, as well as individual characteristics. Anyone suffering from food poisoning is likely to experience one or more of the following symptoms:
- Stomach cramps
- Fever (this is usually mild)
- Malaise (feeling unwell)
- Lethargy (feeling tired)
- General weakness
If you have recently eaten outside, or have visited a new country, and get any of the above symptoms, these can be signs that you are experiencing food poisoning. Please note that symptoms of food poisoning can be similar to symptoms of Viral Gastroenteritis.
How long after a meal will symptoms appear?
There is usually a delay between eating the contaminated food and getting the first symptoms of illness. This period is medically known as the incubation period. Typically, symptoms will appear from a few of hours to days after eating the contaminated food. If symptoms occur within a couple of hours, this suggests that the contamination is caused by a toxin or chemical rather than a pathogen. In rare cases, symptoms can appear from months to years after eating the contaminated meal.
How long does food poisoning last?
Symptoms of food poisoning clear up within 24 to 48 hours. In most cases, symptoms completely disappear within a few days. The time which the infection lasts will depend on your health, the type of food you’ve eaten, and the amount you’ve eaten. If it has been 72 hours and you are experiencing persistent vomiting and/or diarrhea, you should seek medical attention.
Food poisoning treatment
In most cases, food poisoning is self-limiting and can be treated at home. Your symptoms will usually start improving within 2-3 days. These are the things you should do while suffering from food poisoning:
Rest as much as possible
Food poisoning can be quite taxing on your body – you need to conserve as much energy as possible. You should take at least two days off school/work during this period. This is important as food poisoning can be contagious. Additionally, you should give your body a couple of hours before drinking or eating after a bout of diarrhea or vomiting.
Dehydration is caused when your body loses too much fluid, without it being replaced – children and elderly people are more at risk of being dehydrated. Symptoms of dehydration include thirst, feeling tired or dizzy, dry mouth, lips, and eyes, urinating less often than usual, and dark yellow/strong smelling urine. Note that symptoms of dehydration should prompt seeking immediate medical attention. To avoid rehydration you need to drink as much water as possible if experiencing diarrhea or vomiting. These can just be small sips of water regularly spread out through the day. You can also suck on ice cubes or ice chips. If you are unable to keep any fluid down, then you should seek medical attention. Sports drinks which contain electrolytes (salts and other minerals) are also useful. You can also use oral rehydration solutions to replace lost fluids and salts. You should avoid dairy, caffeinated drinks, alcohol, and fizzy drinks.
Oral Rehydration Solution (ORS)
These are sachets which you mix with water which contain vital body salts, sugars, and minerals such as sodium and potassium which you have lost through diarrhea and/or vomiting. Oral Rehydration Solutions are recommended if you are experiencing any symptoms of dehydration. They are particularly recommended for elderly patients and patients with other health conditions. If unsure if ORS is suitable for you, you should seek further advice from a doctor or pharmacist.
Eat whenever you can
It is important to try and eat food whenever you feel ready. You should avoid eating heavy, spicy or fatty foods. You should also avoid eating a large meal at once. You should stick to smaller, light and bland foods, such as:
- plain potato
You should also follow the BRAT diet for the days following your bout of food poisoning.
Let the symptoms run their course
As strange as it sounds, you want diarrhea to run its course. The diarrhea is there to serve a purpose, which is helping your body flush out the bacteria/virus which caused the symptoms. This is why it is not recommended to use any medication or remedies which can stop diarrhea.
You may need antibiotics
If your symptoms last for more than three days, it is possible that you may need antibiotics to clear up the infection. If you’ve symptoms have lasted more than 72 hours, then you will have to see a doctor to discuss your treatment options.
Is food poisoning contagious?
Whether or not your food poisoning is contagious depends on the type of food poisoning you have. Anyone with food poisoning must take steps to prevent the spread of infection:
- Take at least two days off school or work
- If you are infected, do not prepare food for other people
- Do not share towels or clothes with anyone that is infected
- Wash clothes of the infected person with a washing machine on the highest temperature setting
- Regularly clean surfaces, particularly in the toilet (e.g. taps, toilet seat, flush handle)
- Make sure that you and anyone living in the same house washes their hands with soap regularly
When should I see a doctor?
- You have severe symptoms (e.g. vomiting that won’t stop, can’t keep any liquids down)
- Your symptoms don’t improve within 72 hours
- You have signs of dehydration, such as dry mouth, extreme thirst, not peeing for 8 hours, or dark, strong-smelling urine
- Blood in vomit or stools
- Extreme stomach cramps
- Blurry vision
- You are pregnant
- You are over 60
- A child or baby is affected
- You are immunocompromised (have a weakened immune system)
- You have other pre-existing medical conditions, such as kidney disease, diabetes or cardiovascular disease