Symptoms of food poisoning

The symptoms of food poisoning often vary according to the cause but there are symptoms which are common to all types of food poisoning.

These are often referred to as gastrointestinal symptoms or ‘stomach flu’.

Incubation period

What does vary is the incubation period. The term ‘incubation period’ is a medical term for the period of time between exposure to the source of the infection, e.g. bacteria to the onset of the symptoms.

In other words, how long it takes for you to develop the symptoms of food poisoning.

Depending upon the type of food poisoning the incubation period can range from less than an hour to several months. However, in most cases of food poisoning, symptoms appear after 1 to 3 days.

So what are the symptoms of food poisoning?

These include:

• Fever (can be low or high grade)
• Nausea
• Vomiting
• Diarrhoea
• Abdominal pains
• Abdominal cramps
• Lack of appetite
• Chills
• Muscle aches/pains

Nausea, vomiting and diarrhoea are experienced by anyone who contracts food poisoning. In some cases, excessive amounts of diarrhoea will be produced which is also watery in consistency.

In other cases, it can be bloody and also contain mucus, although this is usually a feature of severe diarrhoea.

Stomach (abdominal) pains or cramping is another common feature as is a raised temperature and aches and pains. Generally, you will feel unwell if you have food poisoning.

You may also experience some or all of these symptoms:

• Jaundice
• Poor co-ordination
• Fatigue
• Fits/seizures
• Headache
• Dry mouth
• Poor balance
• Dizziness
• Confusion
• Stiff neck

Sometimes it can be difficult to know if your symptoms are of food poisoning or another type of illness. This is particularly the situation if you develop a headache, aches and pains, vomiting and a high temperature as these are also signs of ‘the flu’.

Severity of symptoms

Everyone is different when it comes to the extent of their symptoms. Some people will experience a mild form of food poisoning whereas others will suffer from a full blown episode.

If food poisoning has occurred as a result of eating contaminated chicken then one can argue that the greater the amount consumed the greater the severity of the symptoms.

So, if for example, you eat chicken which has been infected with salmonella bacteria; if you have eaten a bigger portion of this then someone else you can expect to feel much worse than they will.

This is basically due to the fact that you have ingested a greater number of bacteria than someone else.

These symptoms are worse in people who are considered a ‘high risk’which include:

• The elderly
• Babies and children
• People with a autoimmune disease
• People who have a weak immune system due to cancer treatment (chemotherapy); HIV/AIDS or have undergone a transplant.
• Pregnant women
• People with an underlying medical condition
• People who work in the caring professions

These are discussed further in our high risk for food poisoning section.

How do you know if you have food poisoning? If you are unsure then contact your GP for advice. If you are a parent and suspect that your child may have food poisoning then contact either your GP or health visitor.

Your GP will be able to confirm or reject a diagnosis of food poisoning.

But when do you seek help?

If your symptoms persist, worsen or you fall into a high risk group then speak to your GP.