3.1 Aseptic Procedure
There are specific techniques and methods that
actively assist the user in trying to keep things
clean and sterile. These are known as aseptic
procedures or techniques.
This applies most importantly to the following
items in the Wagtech test kit:
Membrane Filtration Unit:
The internal surface of the sample cup, the
internal surface of the funnel and the filter
base/bronze disc must be sterile before a
microbiological test is carried out (section 3.2).
Petri Dishes:
The internal surfaces of the petri dishes will
come into direct contact with the growth media
during the microbiological test. They must be
free from bacteria when the test begins. They
can be sterilised in a variety of different ways
(section 3.3).
Absorbent Pads:
The absorbent growth pads provide a platform
for the liquid growth media and filter membrane
which sit in the petri dish. There are specific
instructions as to how they must be handled
during the microbiological test (section 3.4).
Culture/Growth Media:
When preparing the media used for the test you
must ensure that the water used to hydrate the
powdered media is sterile. All the vessels used to
prepare the media and into which the media is
dispensed must also be sterilised in a specific
manner (section 3.5).
Membrane Filters/Tweezers:
The membrane filters which capture the bacteria
during the filtration process are supplied pre-
sterilised. They must be handled using sterile
tweezers and never with your fingers.
3.0 Preparation
Every effort should be made to keep the kit and all its components clean and free from contamination.
At all times you should work in a manner that limits the chance of cross contamination of your samples.
9
3
Preparation
Useful to Know
• Methanol is highly flammable and is
classed as ‘Dangerous’ for shipping
purposes. For this reason it is not included
as standard in the kit
•
Methanol can be supplied separately from
the kits but the freight and associated
hazard charges may be expensive
• As an alcohol it can be challenging to find
methanol in certain countries. Pharmacies,
laboratories and hospitals are all possible
local sources
•
When methanol burns in the low oxygen
conditions present in the sample cup of
the MFU, a gas called formaldehyde is
produced. This gas acts as a powerful
disinfectant and ensures a complete
sterilisation of the entire apparatus
•
ONLY Methanol can be used to sterilise the
MFU in the field. Ethanol or Methylated
Spirits are not acceptable as they do not
produce formaldehyde when ignited
• To ensure that the MFU is always ready for
use it is a good idea to sterilise it after each
analysis has been performed.
The MFU must
however be kept in sterile
condition until
the next time it is used
To Next Page
Loading...
Need help?
General
