Types of contaminationa and food poisoning

Cross Contamination

Cross contamination is the transfer of bacteria or other micro-organisms from one food area to another food or area

For example:

* A dirty chopping board will cross contaminate the next food placed on it.

* If you touch raw food like chicken then touch ready to eat food like a sandwich without washing hands or changing gloves (also wash hands) you transfer bacteria onto the sandwich.

•    Storing raw meats above cooked food in a cool room may result in the meat dripping onto the cooked food.

•       Not washing knives or utensils between tasks.

Whenever there is a change in production there must be a full cleaning and sanitizing process to avoid cross contamination.

Viruses

During food preparation contamination can occur by people transferring viruses from themselves to food and then to the person who cats it. Viruses can only multiply in living tissue and cause vomiting and diarrhoea when consumed.

Some raw foods such as oysters, clams and mussels are ‘filter feeders' if harvested from sewage-polluted water they will have a lot of bacteria and viruses in their flesh which will cause viral food poisoning.

This is why it is important to only purchase your fish and seafood from reputable suppliers

Examples of viruses include the Flu and Hepatitis A

It is important to remember that Viruses are easily destroyed by heat so if you cook your foods thoroughly then any viruses present will be killed

Bacteria

Bacteria are the most common cause of food poisoning. Bacteria that cause disease and illness are call pathogens. Small numbers of pathogenic bacteria can be consumed without making you sick because the body's immune system kills them before they can grow to large numbers but if large numbers of bacteria are consumed they will overwhelm our immune system and cause food poisoning.

Bacteria can poison us in two ways:

ü  Infection - if large numbers of some types of bacteria are eaten our bodies normal defense mechanisms are unable to cope and we become sick e.g. Salmonella, Clostridium

ü  Intoxication - Because bacteria are living creatures; they eat and produce waste products. Some of these waste products are poisonous. These are called toxins and can cause illness if consumed, even in small quantities.

Spores

Some bacteria are very smart and can sense when conditions are changing. When they sense that conditions are becoming dangerous for survival they form and become dormant (asleep).

This is like bacteria forming a protective coating around itself which protects it from danger such as heat, lack of moisture, lack of oxygen or change in pH levels of the food (pickling or salting foods)

Spores can survive for many years in this dormant state and cannot be destroyed easily by heat, cold, sanitizers or chemical additives.

Because it is difficult to kill these bacteria it is important to observe the correct heating, cooling and cooking times to control their growth so (hey don't grow to too large amounts which can cause food poisoning.

Spore forming bacteria are most commonly found on raw vegetables, in processed meats, dried herbs and spices and in dried products such as rice, pasta or polenta.

Groups at risk

Each year there are many cases of food poisoning; groups are most likely to suffer from food poisoning:

• People who are already ill (those who are already fighting against viruses or bacteria)
• The elderly (Weak People)
• The very young (not ready to fight against illness)
•  Pregnant women

This is because these groups in society have a much weaker digestive system than normal people. This means they are not as strong to fight off infection as well as other people and can be sick much more easily.

If you are preparing or cooking for any of these types of people you MUST take extra care for these group.