Food Poisoning

boy with food poisoning looking sick sitting on a toiletFood poisoning is an illness induced by eating food or drinks contaminated with harmful bacteria or eating food contaminated with chemicals called toxins. There are two main types of bacterial food poisoning:

  • Food poisoning caused by the consumption of bacteria: This type of food poisoning results from eating bacteria which multiply in the food if it is left in conditions which support the growth of bacteria.
  • Food poisoning caused by the consumption of toxins: Toxins are chemicals that can make you ill and are produced by certain types of bacteria. The toxin is produced in the food before it is eaten and this preformed toxin normally makes you ill very soon after eating the food.

Given the right conditions, millions of bacteria can grow on common, everyday foods. These conditions are:

  • Time – a single bacterium can multiply to over two million in just seven hours
  • Warmth – the ‘danger zone’ temperatures at which bacteria grow best are between 5ºC and 63ºC
  • Food – like any other living things, germs need food to grow. High-risk foods that bacteria love best include dairy products, meat, poultry, fish and shellfish
  • Water – bacteria need moisture to grow. This includes moisture in ‘wet’ foods such as juicy meats, sandwich fillings, soups, sauces and dressings.

For a healthy adult the probability of getting sick from contaminated food is dependent on both the type and number of harmful microorganisms present in the food. For those who are susceptible, namely the very young, and those who are sick or pregnant, where their immune systems are less effective, lower numbers of microorganisms may be required to cause illness.

Symptoms of food poisoning

The symptoms of food poisoning can vary, depending on what type of bacteria has caused the infection. Symptoms can be mild or severe. When you get sick, you usually have one or more of the following symptoms:

  • Feeling sick (nausea)
  • Stomach cramps
  • Diarrhoea
  • Vomiting
  • Fever (feeling very hot)
  • Headaches

Fortunately, most forms of food poisoning last only a short time - between one and three days. However you may feel sick for as long as seven or more days, and in extreme cases the symptoms can be fatal.

How do you prevent food poisoning?

Given the right conditions such as warmth, moisture and time, bacteria can easily grow on food and multiply very quickly. That’s why food that is not properly stored or thoroughly cooked can cause food borne illnesses.

There are four simple steps you can take to prevent food poisoning:

  • Clean – always wash your hands before and after handling and eating food, after visiting the toilet or playing with pets or animals
  • Cook – make sure that food is thoroughly cooked in order to destroy any harmful bacteria that might be present.
  • Chill – keep food cool in order to prevent bad bacteria from growing; make sure that your fridge is at the correct temperature to keep cold foods chilled – aim to keep your fridge at 5°C or below.
  • Separate to prevent cross-contamination – separate raw and cooked foods during storage and cooking and never let raw food, for example raw meat, come into contact with food that is ready-to-eat.

Bacteria are found throughout the environment but they concentrate where a food source is available so it is usual for raw food to come into contact with bacteria, most of which are harmless, but there are some that can cause illness.

What to do if you think you have food poisoning

There is very little you can do to stop food poisoning once you have eaten contaminated food. That is why prevention is the most effective way to stay healthy. The following guidelines will help if you or someone you know comes down with food poisoning.

  • Re-hydration – You lose an enormous amount of fluids during a bout of food poisoning, so be sure to drink plenty of fluids. Whether or not you feel up for it, take frequent sips of water, apple juice, broth, bouillon or an isotonic energy drink with electrolytes. Pregnant women, young children, the elderly and people with serious medical conditions are at an especially high risk of dehydration from food poisoning
  • Medical assistance – If you suspect you have food poisoning, contact a doctor
  • Caring for someone who has food poisoning – You need to take particular care if you are caring for someone who has food poisoning to prevent the further spread of bacteria. Wash your hands thoroughly using anti-bacterial soap and use a bleach solution for cleaning.
  • Reporting – If you suspect that you are sick because you purchased and ate contaminated food, report the incident to your local environmental health officer in your HSE region in the Republic of Ireland and in Northern Ireland, contact your local environmental health officer in your local District Council.