palintest Wagtech Potalab+ (M) User Manual

3
Preparation
14
NutriDisks are the option most commonly used
with the Wagtech Test kits. NutriDisks are larger
than the standard aluminium petri dishes supplied
in the kit but are still designed to fit into the
standard petri dish rack. This allows up to 7
NutriDisks to be incubated at the same time.
To use the NutriDisks they are moistened with
3.0-3.5ml of sterile distilled water. They are then
ready to use immediately. An excess ring of water
surrounding the pad should be visible.
All NutriDisk types are supplied with the
appropriate membrane filters, which are also pre-
sterilised and individually packaged. The membrane
filters are tailored to meet the special requirements
of microbial detection and are available with
47mm or 50mm diameters.
See Appendix 4: Reagents & Consumables
Useful to Know
• Growth or culture media is a substance
designed to support the growth of
microorganisms (bacteria). The media is
a vital part of the microbiological water
quality test
• There are different types of media for
growing different types of bacteria. The
Wagtech kits use Membrane Lauryl Sulphate
Broth (MLSB) as the growth media
•
MLSB is a differential media which means
it can distinguish one microorganism type
from another growing on the same media.
It uses the biochemical characteristics of a
microorganism growing in the presence of
specific nutrients or indicators (such as
Phenol Red) added to the medium to visibly
indicate the defining characteristics of a
specific microorganism
• MLSB is the growth medium for Coliform
bacteria and Escherichia coli (E.coli). It
feeds coliform bacteria but inhibits the
growth of any non-target organisms that
may be present in the sample
• The MLSB in the kit is supplied as a fine
powder. This increases its shelf life and
makes transport and shipping easier.
Preferably it should be stored in a dark
environment away from extremes of heat
and moisture
• Typically in its powder form the shelf life
of the MLSB is 12 months
•
In order to be used in the microbiological
test the MLSB has to be prepared in liquid
form. When water is added to powdered
MLSB a deep red liquid is formed
• Coliforms are identified by their ability
to cause a colour change in the growth
media when incubated. MLSB contains
lactose as the major carbon source, which
during incubation is degraded to acid by
E. coli and coliform bacteria; this is indicated
by a change of the colony colour from
red/pink to yellow

palintest Wagtech Potalab+ (M) Specifications

General

Brand	palintest
Model	Wagtech Potalab+ (M)
Category	Measuring Instruments
Language	English