Food Poisoning
When you consider the number of meals
consumed, the chances of getting food poisoning are really quite
low. Nevertheless, it seems that food poisoning is on the increase
around the world. In the USA there are about 10,000 needless deaths
from food poisoning each year. On top of this, there are a further
50 million non-fatal cases of food poisonong.
Before the days of refrigeration, when much more
preparation and processing of food occurred at home, people were
more aware of the dangers of food poisoning. However shoddy
handwashing and poor attention to hygiene don't give us the whole
picture of why food poisoning is on the increase in the developed
world.
With the increase of mass food production, the need
for increased storage time; difficulty of maintaining suitable
temperatures during transport; changes in the methods of
food-processing all magnify the risk of contamination. Another
reason may be that doctors are looking for and reporting it,
whereas once it went unreported.
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What Causes Food Poisoning?
Micro-organisms are the most common cause of
food poisoning. As they occur in the soil, air, water and on
animals, it is highly likely that they are present on all uncooked
foods.
Bacterial food poisoning is of two
types:
- Infection by the bacteria itself which grows
rapidly once inside the digestive tract of humans. This causes
nausea, diarrhoea and vomiting. Salmonella and Campylobacter Jejuni
are responsible for this type of food poisoning.
- Infection through the eating food which
contains toxins produced by bacteria, such as Clostridium botulum,
Staphylococcus and Bacillus Cereus.
Salmonella
Salmonella contamination is the leading
cause of food poisoning, causing diarrhoea, cramps, nausea and
vomiting. Salmonella is common in raw meat, poultry and eggs and
although rarely fatal, it can kill the elderly, very young or ill.
Typhoid, a disease no longer common, is caused by a strain of
Salmonella.
Escherichia Coli
Although E Coli is a normal inhabitant
of the stomach, and quite harmless, some strains can cause
infection, and can be deadly. E. Coli is one of the most common
causes of upset stomachs in travellers. It is transferred through
faeces, and affected animal products. Two strains which occur in
under-cooked meat produce toxins which attack our kidneys and can
result in death.
Poor sanitary habits increase the possibility of E
Coli food poisoning; the main symptom being diarrhoea.
In 1996, an outbreak of E. coli infection among
Japanese school children resulted in 6000 children becoming ill and
two actually died.
Campylobacter Jejuni
Campylobacter is common in chickens
and cats and dogs. Consuming undercooked poultry is the main source
of this kind of food poisoning, although it is found in other
animal meats and raw milk. Contaminated water is another possible
source.
Campylobacter is the most common cause of infectious
gastro-enteritis in humans, causing diarrhoea, cramps, fever and
bloody stools.
Listeria
Listeria can grow in cold or very hot
climates, with or without oxygen, particularly in soft cheeses,
pates, and meat products which do not contain preservatives. It is
of greatest risk when processed foods haven't been prepared
hygienically, although it doesn't normally cause problems, as it is
destroyed by cooking at 70 Degrees Celcius for several minutes.
Listeriosis is particularly dangerous for pregnant women, causing
stillbirths and miscariages.
Clostridium Botulinum
Although rare, botulism is the
deadliest type of food poisoning - it has even been considered for
germ warfare. Caused by an anaerobic organism "Clostridium
botulinum", it can occur in home bottled or canned foods where
oxygen isn't present.
Botulism develops within 12 - 36 hours after eating
and the early symptoms include nausea and vomiting, tiredness,
dizziness and headaches, stomach pains and diarrhoea. As the
illness progresses, difficulty in speaking and swallowing occurs
and finally death from respiratory failure, if not treated in
time.
Staphylococcus Aureus
Staphylococcus Aureus (Golden Staph)
produces toxins as it multiplies in foods high in protein, such as
meats, poultry, eggs, custards and fish. Such foods should be
refrigerated as soon as prepared. Heat does not destroy the toxin,
which causes retching, vomiting, cramping, diarrhoea, watery
stools, sweating, cold clammy skin and dehydration.
Bacillus Cereus
This bacteria is found in starchy foods and
spices. Of particular danger in rice, where the spores may be
present and boiling doesn't kill the bacteria but allows them to
germinate. If the rice is not chilled, but left at room
temperature, the bacteria multiply rapidly, producing toxins which
can cause violent food poisoning.
Who gets food poisoning?
The most likely people to suffer from
food poisoning are the elderly, young children and people who are
unwell. Healthy adults are usually less likely to be
affected.
In 1994, there was an outbreak of food poisoning at a
youth camp in Australia, caused by clostridium perfringens. Cold
chicken had been served, which had been cooked the day before, and
left to cool for more than two hours before being refrigerated. As
a result 230 youths had gastroenteritis, 13 having to be
hospitalised.
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