First 218 words of the document:
B3: Using Micro Organisms Safely
If the microorganisms that we want to use are contaminated, the
other microorganisms that are present may produce harmful
So it is only safe to use microorganisms if we have a pure culture
containing only one particular species of microorganism.
Microorganisms can be grown in a culture medium containing
carbohydrates as an energy source, mineral ions, and in some
cases supplementary protein and vitamins.
These nutrients are often contained in an agar medium which can
be poured into a Petri dish.
In order to prepare useful products, uncontaminated cultures of
microorganism are required.
Petri dishes and culture media must be sterilised before use
to kill unwanted microorganisms
inoculating loops used to transfer microorganisms to the
media must be sterilised by passing them through a flame
the lid of the Petri dish should be taped down to prevent
microorganisms from the air contaminating the culture.
In school and college laboratories, cultures should be incubated
a maximum temperature of 25 °C which greatly reduces the
likelihood of pathogens growing that might be harmful to humans.
In industrial conditions higher temperatures can produce
more rapid growth.