What Is Food Poisoning?
Food poisoning occurs when a person gets sick from eating food that
has been contaminated by unwanted microorganisms or the toxins they
produce. This condition is called ‘Food Poisoning’, or more properly,
gastro-enteritis. The most common symptoms of food-borne illness
include stomach cramps, nausea, vomiting, diarrhoea and fever.
Who Gets Food Poisoning?
Globally, it seems that between one in three and one in four people
gets food poisoning every year, so everyone is at risk – simply
because we must eat.
Most cases of food poisoning go unreported to health agencies. This is
partly because, for normal healthy adults, food-borne pathogens only
cause mild symptoms and medical help may not be necessary. In the UK
it has been estimated that for every 136 cases of illness in the
community; only 23 people will see a doctor, only six samples will be
sent to a laboratory for identification of the organism causing the
illness, and just one case will be identified.
Food poisoning is much more serious in young children, and in frail
and immuno-compromised people. Diarrhoea and vomiting can, for
example, cause life-threatening dehydration in babies and young
children. About 5,000 people die every year from food poisoning in the
USA. Most of these people were probably already vulnerable at the time
of the infection. People with HIV are very susceptible to food
poisoning because their immune systems are impaired.
It is reported that males suffer more from gastro-enteritis than
females. A possible reason for this is because fewer men wash their
hands after using the lavatory than women (33% compared with 66%,
taking an average of 47 seconds as against 79 seconds).
Why Don’t We Hear About Food Poisoning In South Africa?
In South Africa, food poisoning is a notifiable disease, but the
surveillance system is not effective. South Africa reports just a few
hundred cases of food poisoning per year, whereas the incidences are
more likely to be in the region of hundreds of thousands of cases.
The effective surveillance and reporting systems of the UK, USA and
many European countries has the effect of making people aware of the
dangers of food-borne disease and of how to take preventative steps.
Outbreaks of food poisoning are often covered in the newspapers
overseas. South Africans are much less aware of food-borne illness
because no public health campaigns are run to ensure that the food we
prepare is safe to eat; and there is also little press coverage on the
What Causes Food Poisoning?
Food poisoning is caused principally by bacteria and viruses. Bacteria
may grow in the food so that the food, when it is eaten, contains
enough bacteria to colonise the gut lining and cause food poisoning
symptoms. Other types of bacteria may not grow in the food itself; in
those cases the food acts only as a carrier. Dysentery bacteria are
usually only carried in food; only a few dysentery bugs are needed to
cause severe illness. Diarrhoea-type food poisoning normally takes
between 24 hours and 72 hours to set in after the contaminated food is
eaten. If you get food poisoning you need to think back to what you
have eaten over the last couple of days and not simply blame the
symptoms on the last thing you ate.
Viruses never grow in food, but are passed directly from people to
food. Children are often affected with tummy viruses and epidemics are
common in schools during the winter months, frequently because of lack
of personal hygiene.
Some bacteria, particularly one type found in the nose and throat of
most adults and nearly all children, can multiply in certain foods and
produce a toxin in the food. When the food is eaten, it is the toxin,
not the bug, which causes violent vomiting within a few hours of
eating the food.
What Foods Carry Microorganisms?
All foods carry microorganisms. Bacteria and other organisms are all
around us, in and on our bodies. The vast majority do us no harm and
many are beneficial. Indeed some of our most delectable staple foods
are made by using microbes. These include bread, wine, beer, cheese
yoghurt, and salami. Some foods are more prone than others to be
potential carriers of food poisoning organisms. These foods are
principally raw meat, poultry, milk, and seafood.
Meat And Poultry
Food-poisoning organisms are often associated with the gut of humans,
animals and birds. Therefore, any food that is contaminated with
faeces has the potential to make you sick. Meat and particularly
poultry are easily contaminated with faeces during the slaughtering
and dressing of the meat, so you should treat all raw meat products as
if they were contaminated.
Meat and poultry should be stored away from cooked foods in drip-free
dishes. Great care should be taken not to cross-contaminate cooked
food with raw meat or poultry. Use separate chopping boards and knives
and wash your hands when moving from handling raw meat to prepared
food. Meat and poultry needs to be well-cooked because cooking
destroys food-poisoning organisms and makes it safe to eat.
Milk is another food that has the potential to be contaminated with
faeces. (Remember that milk and faeces both come out of the same end
of a cow!) Milk is pasteurised for a very good reason. Pasteurisation
is designed to kill harmful food poisoning micro-organisms so that it
is safe to drink. Never drink un-pasteurised milk and NEVER give it to
children. Avoid cheese that is advertised as being made from
un-pasteurised milk (this can sometimes be found in ‘health’ stores
and produce markets). It has the potential to be unsafe.
Fruit, Vegetables And Salads
With the trend towards healthy eating and the rising consumption of
fruit and vegetables, care should be taken if such foods are eaten
raw. Obviously if food is grown in the fields and fertilised with
manure that has not been properly composted, or fertilised just before
harvest, the potential exists for the vegetables to carry food
poisoning organisms. Always wash salad, vegetables and fruit well
using potable water (i.e. fit for drinking). The cooking of vegetables
destroys harmful microorganisms, so fresh cooked vegetables are safe
If travelling overseas to less-developed countries, it is a good idea
to soak fruit and vegetables in Milton’s solution to destroy any
harmful microorganisms on the surface. Remember that the water might
also be of suspect quality and Milton’s will disinfect it too.
A small percentage of raw eggs can carry food poisoning bacteria in
the yolk or white. It is wise not to give children undercooked or
lightly cooked eggs. Avoid all home recipes that require the use or
raw or lightly cooked albumen and yolk, such as chocolate mousse and
Since water is a component of most food and drink, we take in large
amounts of it every day through what we eat and drink. Both drinking
water and water used to prepare food must be safe. Water contaminated
with sewerage is extremely dangerous and is a major source of illness,
including cholera. If you are away from home and in doubt about the
quality of the water, always boil it before drinking. In South Africa
the municipal water is of good quality.
F.A.C.S. Scientific Director. 2009. (Update 2017 imminent)