Foods may considered to be microbiologically unsafe owing to the presence of microorganisms which may invade the body (such as Salmonella,. Listeria, E. coli) or those which produce a toxin ingested with food (e.g. Clostridium botulinum, Staphylococcus aureus and Bacillus cereus).
There are six types of microorganism that can contaminate food bacteria, viruses, parasites, toxins, yeasts and molds.
The first four are considered pathogenic microorganisms meaning they can cause illness when ingested.
These can be present in food simply because they are part of the natural environment.
The two main features of pathogenic microorganisms that elicit their disease causing mechanism are:
*ability to invade tissues
*ability to produce toxins.
In the former cases, invasiveness encompass mechanism for colonization, for bypassing of host defense and for production of extracellular compounds which facilitates invasion.
The food contains a rich medium for bacterial growth; protein, fat, carbohydrates, minerals vitamins and a high percentage of water it an excellent substrate for growing of bacteria including pathogenic bacteria that can be in the environment and prosperous medium for enzymatic activity.
Pathogenic microorganisms
