This is the section where we look at the particular bacteria that cause food poisoning in this country, these are as follows:-
Salmonella
Clostridium perfringens
Staphylococcus aureus
Bacillus cereus
Clostridium botulinum
Escherichia coli
You will realise these are all pathogenic bacteria as they make people ill.
Salmonella
Public enemy number 1 is a pathogen that you may well have heard of - Salmonella. Salmonella
causes more cases of food poisoning than any other bacteria in England and Wales.
There are over 2,000 different types of Salmonella, some with very exotic names,
such as, Salmonella montevideo or Salmonella cholerae suis, but you will
be pleased to know that you just need to remember the family name, Salmonella.
The important facts about Salmonella that you should know, are where it comes from i.e. its source, and what symptoms you can expect if you become infected with Salmonella.
Revision: You will remember from Part A that the incubation or onset period is the time between a person eating contaminated food and becoming ill.
Clostridium perfringens
The second most common cause of food poisoning in England and Wales is a bacterium
with the name of Clostridium perfringens.
It causes far fewer cases of food poisoning than Salmonella. However, because it can form
spores, it is usually a problem when food has been cooked in advance and reheated
before it is served (if you can't remember the importance of spores, look back
to the definition of spores
before you continue). For this reason it is associated with outbreaks
at institutions, such as residential homes or at large functions like wedding
celebrations. In such cases, the food is often cooked in advance and may be
cooled too slowly, allowing the spores to germinate, and the bacteria to multiply
quickly.
Staphylococcus aureus
Another major food poisoning organism we need to know about is a bacterium that is commonly
found on the skin and in the nose and throat of healthy people, including those
who work in the food industry! This is Staphylococcus
aureus. Because this germ can live happily on healthy bodies as well
as in cuts and boils it is vital for food handlers to have high standards of
personal hygiene. More about this later. Staphylococcus aureus is also
found in raw milk.
Bacillus cereus
You may be aware of one other type of food poisoning. Bacillus cereus is
the bacterium that can cause problems if rice is not handled correctly. It is
a germ that commonly contaminates rice and like Clostridium perfringens
is able to form spores and is therefore associated with reheated rice dishes.
Clostridium botulinum
Another form of food poisoning that you might have heard of is botulism. It is caused
by the bacterium Clostridium botulinum.
Fortunately, it is very rare in Britain, as its symptoms are very serious. It
does not cause the normal sickness and diarrhoea but instead it attacks the
nervous system and people find it difficult to breathe or swallow. Paralysis
occurs and it is often fatal. It is a form of food poisoning that is associated
with canned foods and smoked fish.
Escherichia coli
The final bacterium we shall look at in detail is one that caused the most serious outbreak
of food-borne disease in Britain; Escherichia coli, better known
by it's shorter name E. coli. There are a number of different types.
One type, known as E. coli O157, is the bacterium that led to the death
of 18 people in Lanarkshire in 1996, following the consumption of meat products
prepared in a butcher's shop.
This was the most deadly outbreak of food-borne disease that has occurred in Britain.
The main source of E. coli is raw meat, especially beef and lamb. Although it is quite a rare cause of illness, it can be very serious for those that become infected, particularly young children and old people.
food-borne diseases that you should be aware of, although we shall not be looking at them in detail. They include Campylobacter, (see part A) Typhoid, Cholera, Dysentery (all these can also be carried in contaminated water as well as on food) and Listeria (which has been involved in outbreaks associated with soft cheese, pâté and salads).
Can you remember what the difference is between food poisoning and food-borne
disease?
Take a moment to write your answer down and then check your answer with the
one HERE
The bacterium responsible for most cases of food poisoning in England and Wales is Salmonella of which there are over 2000 different types. It is found in raw poultry, meat, eggs and milk, as well as in the guts of animals and man.
Other important food poisoning bacteria are Clostridium perfringens, which can form spores, Staphylococcus aureus, which lives on the skin and in the nose and throat of people and can produce toxins in food, and Bacillus cereus, also a spore-former and commonly found in rice. E. coli is the cause of a serious food-borne disease that can kill, particularly the very young or old.
You will now need to sucessfully complete the section test before you can move on to Part C dealing with the Prevention of Contamination and Food Poisoning. Complete the test by clicking on the Take Section B Test button at the left of the screen.