Food poisoning symptoms

Siski Green / 28 May 2014

What causes food poisoning and how long does it last? Read our guide to learn how to spot the symptoms of food poisoning and find out what you can do to prevent it.

Food poisoning, aka Delhi belly, doesn’t just affect people abroad, it can happen to anyone at any time. A simple cooked egg at home, a sandwich from the petrol station, or even a fancy meal in a well-established restaurant – you could experience food poisoning in any of these places. While it’s only rarely fatal, food poisoning can be extremely severe in young children, the elderly, and those who have an impaired immune system. So arm yourself with knowledge about the most common types of food poisoning and how to avoid them.

Salmonella food poisoning

Salmonella symptoms

Usually within a day or two of ingesting the salmonella bacteria, you’ll suffer with the following symptoms:

  • Vomiting
  • Diarrhoea
  • High fever
  • Stomach cramps

How long does salmonella poisoning last?

Salmonella poisoning can last from four days up to a week. When you suffer from food poisoning dehydration is a concern, so it’s important to make sure you drink lots of fluids during this time. Although the immediate symptoms of diarrhoea and cramps dissipate relatively quickly, be aware that your digestion may not return to normal for several months after infection.

Where do you get salmonella poisoning from?

Fresh eggs, products from eggs (such as fresh mayonnaise*), raw meat, unpasteurised cheese.

*The mayonnaise you buy in a jar is not a high risk food when it comes to salmonella. That’s because it has been treated during production. Fresh mayonnaise, however, is made with raw egg and so does pose a higher risk.

How to avoid salmonella poisoning

Cooking. Avoid eating runny eggs and other nearly-cooked raw dairy or meat products and you’ll kill all salmonella germs. Remember too, that other foods might be contaminated if you don’t wash your hands if you don’t wash them after handling eggs, for example.

E. coli food poisoning

E. coli symptoms

  • Severe stomach cramps and tenderness
  • Nausea
  • Vomiting
  • Bloody diarrhoea, particularly, is associated with E. coli.

How long does E. coli poisoning last?

E. coli poisoning symptoms are usually gone within a week, but in children and older adults E. coli may affect the kidneys, even causing kidney failure.

Where do you get E. coli poisoning?

E. coli is passed relatively easily from person to person which is why washing your hands is so important.

Common infected foods include minced meat (such as that in spaghetti bolognese) because E. coli bacteria from animals’ intestines can get mixed in with the meat; unwashed or poorly washed vegetables, particularly salad leaves; restaurants where chefs don’t wash their hands properly after going to the toilet.

How to avoid E. coli poisoning

Wash your hands frequently and cook meat to a high temperature (71ºC or 160 ºF) which will kill E.coli bacteria. Wash all fruit and vegetables thoroughly before eating. Take care with the water you drink – a stream, for example, could well be contaminated, particularly if it is close to a farm or area where animals defecate.

Camplobacter food poisoning

Camplobacter symptoms

This bacteria doesn’t usually cause as severe symptoms as the others, mentioned above, but for older adults or those with compromised immune systems, there can be complications which can lead to a more severe illness. Around two to five days after eating foods infected with camplobacter, a person will suffer from the following symptoms:

  • Diarrhoea
  • Stomach pain
  • Fever
  • Vomiting
  • Headache

How long does camplobacter poisoning last?

Camplobacter poisoning symptoms are usually gone within a week. Some individuals may be infected with camplobacter and show no symptoms at all.

Where do you get camplobacter from?

Chicken meat is the most common source of camplobacter, as well as unpasturised milk and contaminated water.

How can you avoid camplobacter poisoning?

This bacteria is also killed with heat, so make sure you cook all your food, especially chicken, thoroughly (to 74ºc/165ºF). Use a separate chopping board for raw chicken and meat, and wash your hands thoroughly with soap afterwards.

Listeria food poisoning

Listeria poisoning symptoms

While many of the symptoms of listeria are similar to other types of food poisoning – vomiting, fever, diarrhoea – patients also often experience a stiff neck and confusion.

Where do you get listeria poisoning from?

Listeria often comes in the form of outbreaks, when a particular food from a company or farm causes infections via its food products. Foods eaten raw such as melon or celery can be a source, as can soft cheeses made from unpasteurised milk such as brie or camembert. Ready-to-eat luncheon meats and hot dogs are also a source of listeria.

How to avoid listeria poisoning

Although pregnant women are the most susceptible to this bacteria, older adults are four times more likely to be infected than other, younger non-pregnant adults. Those with diabetes are also at higher risk.

Steering clear of all soft cheese, liver pâte, and unpasturised milk will certainly help and if you’re particularly vulnerable to the bacteria (ie your immune system is compromised) this may well be your best bet. Listeria can grow on foods in your fridge and the only way to kill the bacteria is to cook that food. So if you can’t live without your camembert or brie, at least grill it to a high temperature first.

Tips to avoid food poisoning

Be extra aware in summer.

E. coli outbreaks are ten times more common in the summer, and all of the other food poisoning infections mentioned above are also more common in summer. This is probably because people are more likely to cook meat on barbecues, which they don’t use that often (and so may not know if the meat is thoroughly cooked), plus they may be less fastidious about washing hands, compared to the cold and flu season. Finally, summer is also a time when more fresh fruit and salad vegetables are eaten – if eaten without careful washing, this potentially exposes you to more bacteria too. Read our guide to barbecuing chicken safely.

Stick to whole foods

Keep foods whole rather than cut up. Bacteria multiply much faster on smaller surfaces such as those of sliced fruit or vegetables rather than whole.

Count to 20 while washing hands

A squirt of soap and a quick rub won’t get rid of those germs. Scrub for 20 seconds, making sure you get between your fingers and under your nails - and don’t just wash your fingers, go all the way up to your wrist.

Invest in a thermometer

Is it too pink? Are those juices really clear? There’s only one way to know if meat is properly cooked - by using a thermometer. Each type of meat should be cooked to a different high temperature, with the highest being 74ºC/165ºF for poultry, ground beef/veal/lamb and leftovers and casseroles; and the lowest being 63ºC/145ºF for fresh pork and ham, and steaks and chops.

Let it rest

Letting meat rest before you eat not only makes it taste better as a lot of the juices are reabsorbed, the temperature also continues to rise a little, helping to ensure all those germs are killed.

Drink plenty of liquid

If you are infected, maintaining liquid intake is of the utmost importance as dehydration is the most common complication. Liquid rehydrating solutions contain some salt to help rehydrate you (salt is necessary for your body to retain water). And if you can stomach food, try easy-to-digest foods like soup, soft vegetables (such as cooked carrots) and avoid foods that are dairy-based, or high in fat, fibre or sugar.

The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.