DelAgua Portable Water Testing Kit, Руководство пользователя

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DelAgua Water Testing Kit Manual | Version 5.1
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Note: It is important that counting is completed as soon as possible after the petri
dishes have been removed from the incubator (certainly within 15 minutes) as the
positive colonies will change colour on cooling and standing.
5.4.6 Counting Colonies and Recording Results
Once the incubation period is complete,
remove the petri dishes and their holder
from the incubator. Carefully lay the plates out,
in sample order, on a table to allow effective
results comparison.
Check the stack blank first. The result of
this particular plate will dictate if ANY of
the other plates can even be considered. If the
stack blank is positive then either the media or
the plates could be contaminated. A negative
1
2
Squares 3mm × 3mm
Yellow colonies
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Note:
It is recommended that the mains supply option be used wherever possible.
When used in this way, the charger unit will operate the incubator and at the same
time charge the battery. If the mains electricity fails the internal battery will operate the
incubator. (See
Appendix K for more information). ƒ
stack blank will appear the same colour as the
original media, possibly with slight lightening
due to a temperature/pH change. A positive
stack blank will likely be a yellow colour. The
indicator in the media (phenol red) will change
its colour from red to yellow as the pH drops
due to biological activity. In the event of a
yellow stack blank, all other samples should be
discarded and the process repeated.
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