palintest Wagtech Potalab+ (M) - Sterilising Aluminium Petri Dishes; Media Preparation

3.3 Sterilisation of the
Aluminium Petri Dishes
Your Wagtech test kit is supplied as standard with
a set of aluminium petri dishes. These are used
during the microbiological analysis. They are used
to hold an absorbent pad soaked in growth media.
A set of 20 petri dishes is supplied with each
incubator complete with rack, which is used to
lower them into the incubator and hold them
in place during the incubation cycle.
The petri dishes are 50mm in diameter and are
designed to accommodate the 47mm diameter
absorbent pads and filter membranes used in the
microbiological test.
They are manufactured from aluminium so that
they can be re-sterilised and used again and again.
Before use it is important that these petri dishes
are sterile. They can be sterilised in a number of
different ways:
• Autoclave/Pressure Cooker @ 121ºC
for 15 minutes
• Immersion in a pan of clean boiling water
for 15 minutes then allow to air-dry
• Heating in conventional oven at a temperature
of greater than 180ºC for 30 minutes
3.4 Preparation of the Aluminium
Petri Dishes/Absorbent Pads
1 It is recommended that the absorbent pad
dispenser is sterilised before use. Add a few
drops of methanol to the contact area, wipe
with a clean cloth and place on work surface
to dry.
2 Attach the absorbent pad cartridge to the
dispenser, locking it into place.
3 Remove the lid
of the petri dish
and dispense a
pad into the dish
by sliding back
the grooved lever
using your thumb.
4 Once the pad is
safely in the petri
dish, immediately
replace the petri
dish lid. Take care
when handling the petri dish. Never touch the
internal surfaces of the petri dish, always hold
the dish by the side.
5 Repeat the procedure
until the required
number of petri
dishes are prepared
and store the dishes
in the petri dish rack.
Place the rack in the
incubator for safe
storage until ready
for use in the field. The media is added to the
absorbent pads when on site at the time of
sample processing.
3.5 Media Preparation Procedure
The Potalab
®
+ (M) is supplied
with five Media Measuring
Devices (MMD). MMDs are pre-
sterilised polypropylene containers.
The blue screw cap lid features an
integrated spoon/spatula.
The MMD is used to prepare the
culture media in small quantities for
optimum ease of use in the field.
Each MMD can hold 25ml of liquid
media, enough for ten microbiological tests.
The MMD allows end-users to prepare sufficient
media for daily requirements and removes the
problems associated with preparing and storing
large amounts of liquid media.
The MMDs can be re-sterilised after each use,
without affecting product performance.
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3
Preparation