A quick re-cap - you will remember that we said that food poisoning was caused by eating food contaminated by harmful substances or by harmful micro-organisms living on the food. Well what does this really mean?
Most cases of food poisoning are caused by eating food on which large numbers of harmful bacteria have been living. Bacteria are "living micro-organisms" and they are very, very small. Therefore, they can only be seen through a powerful microscope. Harmful bacteria are Public Enemy No.1 for food handlers as they are the cause of most of the 100,000 cases of notified food poisoning a year. You will learn a lot more about bacteria in the next section.
However, there are other micro-organisms that can also cause food poisoning:
Viruses - even smaller than bacteria, these micro-organisms live on and in people and are responsible for a number of cases of food poisoning a year.
Moulds - we are probably more familiar with these micro-organisms than the others as when they grow on jams and fruit, for example, they can become visible to the naked eye.
Although most are probably harmless, some can produce very powerful poisons in the food in which they grow. Besides the above micro-organisms, other harmful substances can cause food poisoning:
Poisonous plants - occasionally poisonous foods are used by mistake. Perhaps toadstools used instead of edible mushrooms are the most obvious example. In other cases, certain vegetables, such as red kidney beans, need to be cooked to destroy natural poisons within them. Eating them uncooked can lead to illness.
Poisonous fish - occasionally poisons can build up in fish before it is canned or processed in some other way. Unfortunately the processing will not destroy the poisons and illness will occur in people who eat the fish. This type of food poisoning is quite rare.
The other cause of food poisoning that you need to know about is chemical or metallic poisoning. Poisonous chemicals can find their way into food in a number of ways.
What kind of chemicals used in a food business might cause food poisoning if they find their way into food? Make a list of your ideas before checking the answer by clicking HERE
Metallic food poisoning is a form of chemical poisoning that occurs when metal in contact with food is absorbed by it. This can happen if acid fruit is stored in poor quality enamelware or fruit juices attack copper pipes used in a vending machine, releasing small quantities of metal into the food or drink.
When you read the newspapers over the next few weeks look out for reports about outbreaks of food poisoning or concerns about the contamination of food. Note whether the illness is due to a micro-organism, chemical or some other type of contamination. Also look in the local papers for any reports of food businesses that have been prosecuted for poor food hygiene or selling contaminated food. How much harm do you think such publicity will cause the business?