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October 1999

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Subject:
From:
Sharon Wood <[log in to unmask]>
Reply To:
Date:
Fri, 22 Oct 1999 11:56:38 -0700
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Antti,
I am not sure where the -50C came from, but I have stored microbial
cultures,
both ATCC and environmental isolates) at -70C ultra low freezers and in
liquid
nitrogen.  We checked their viability and metabolic characteristics on
an as
needed or yearly basis.  There were some adverse effects on some of
organisms,
mainly among the more fastidious gram positive, non-sporeforming rods.

It is confusing the way it is written, but I would interpret not more
than -50
C to mean not warmer than, but that it could be colder.
Sharon Wood
[log in to unmask]


Antti Mikkola wrote:

> Dear members of the forum
>
> I have two questions about the correct way of storing microbial cultures
> at low temperatures.
>
> USP 24 (under <51> Antimicrobial Effectiveness Testing, Test
> Organisms) defines that the vials, containing glycerol-protected cell
> suspensions must be stored in the following way: "Store the vials in
> liquid nitrogen or in a mechanical freezer at no more than -50 C."
>
> What is the rationale behind the limit -50 C?
>
> Would it be acceptable to store the cultures at temperatures less than
> -50 C, provided that it can be shown that viability or other characteristics
> are not adversely affected during the maximum storage time?
>
> Many thanks in advance for your help
>
> Antti Mikkola
> Orion Pharma
> Finland
>
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