Food Poisoning refers to illness that results from eating contaminated or spoilt food. It is a common occurrence as almost everyone will have food poisoning at least once in their lifetime. Most cases resolve without treatment while some may require treatment, including the need for hospital admission. 

What are the symptoms of food poisoning?

Symptoms experienced by different people who have food poisoning may vary, depending on the sources of the infection. They may include:

1. Nausea
2. Vomiting
3. Abdominal pain
4. Loss of appetite
5. Generalised body weakness
6. Fever
7. Headache
8. Scanty / bloody urine

What causes food poisoning?

The common microorganisms implicated in food poisoning are:

1. Bacteria – This is the most common cause of food poisoning, with Escherichia coli and Salmonella being most dangerous. 
2. Parasites – These are not as common as bacteria. Their symptoms are more subtle, as they may live inside the intestine undetected for years. Toxoplasmosis is the most dangerous of the food poisoning attributed to parasites which may result in death.
3. Viruses – These are also not as common as bacteria causes of food poisoning. These include hepatitis A which affects the liver. Their effects are usually mild and usually self-limiting

These organisms contaminate food items regularly. They are however destroyed by heat when food is well cooked. They easily cause problem when food is eaten raw without undergoing cooking process or when poorly cooked. Sometimes, even cooked food gets contaminated after being served, especially when the server has poor hygiene practices. The organisms can also contaminate drinking water.

What are the risk factors for food poisoning?

Even though no one is immune to having food poisoning, certain people in the population are more at risk of having food poisoning than others. These include:

1. Young children – Children under the age of five years may be at high risk because of their immature immune system. When affected, they rapidly lose water and electrolytes more than adults and are therefore more susceptible to dehydration and electrolyte imbalance.
2. Elderly – People who are 65 years and above are also more vulnerable to food poisoning than others because of the slow response of their immune system to the infecting organisms at that age.
3. Pregnant women – Pregnant women may be at higher risk of food poisoning than others because of some modification in immune system response to accommodate the growing baby and hormonal influence of pregnancy. 
4. Compromised immune system – Those with compromised immune system may be at a greater risk of food poisoning. These include patients with HIV/AIDS, autoimmune disease, those on prolonged steroid therapy etc.

What investigations are required for food poisoning?

In most cases, food poisoning may be diagnosed based on history and examination. When necessary, especially in severe cases, you may be required to carry out some of the following investigations:

1. Blood tests – This may include: complete blood count, blood culture etc, which may be necessary to determine the severity of the condition and identify specific organisms causing the problem as well as the appropriate antibiotics to use.
2. Stool test – This may help in identification of the offending organism
3. Test on food remnant – This may also be helpful in identification of the offending organisms
4. Urine test – This may be necessary to evaluate whether or not you are dehydrated (lost significant water volume) following diarrhoea and vomiting occasioned by food poisoning. 

How is food poisoning treated?

In majority of cases, food poisoning can be treated at home, resorting to hospital management only if symptoms persist. Steps to take for home treatment include the following:

1. Bed rest – This is important to conserve energy and reduce insensible water loss (through sweating and heavy breathing / hyperventilation) 
2. Adequate hydration – Adequate fluid intake helps replace fluid loss from diarrhoea and vomiting. Oral rehydration therapy, coconut water, and diluted fruit juice can help restore body water, energy and electrolytes lost through vomiting and diarrhoea. You may avoid drugs that stop diarrhoea such as loperamide during this period, as the body may be trying to eliminate the toxin through induction of diarrhoea. Stopping it in this case may then be counter-productive. 
3. Treat identified causes – For food poisoning that doesn’t get cleared off on its own, prescription medication may be necessary, according to the identified causative agent. This may be more important for the vulnerable groups (children, pregnant women, older adults and the immune-compromised). The prescription medication may target bacteria or parasites. Antitoxin against Clostridium botullinium, a toxin-forming bacterium, may be necessary.
4. Hospital admission – If you have a severe form of food poisoning, passing fluid through your veins may be necessary for hydration as oral hydration may be insufficient for quick recovery. The duration of hospital admission depends on the severity of the food poisoning.
5. Nutrition – While on treatment, avoid solid foods that may require time to digest until symptoms have subsided. You may make do with liquid and semi-solid foods such as diluted fruit juice, pap, rice, vegetables, banana etc, during the recovery phase. During this period, you may need to avoid fried and fatty foods, milk and cheese, highly seasoned and spicy foods as well as foods high in sugar. Alcohol should also be avoided. 

How can food poisoning be prevented?

Food poisoning can be prevented by following these steps 

1. Safe handling of food to prevent contamination
2. Ensure thorough hand-washing before cooking, serving and eating food.
3. Food not to be eaten immediately should be properly covered to prevent contamination
4. Food, including meat, eggs, etc, should be thoroughly cooked, as heat kills many of the contaminants 
5. Avoid eating food from sources you are not sure of the safety of the food
6. Avoid eating dairy products such as meat, milk, eggs etc in raw form
7. Wash fruits and vegetables thoroughly before eating them
8. Persons suffering from diarrhoea and vomiting should not prepare food
9. Avoid drinking water from unknown sources