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July 2020


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AMARO Fernanda BRASIL <[log in to unmask]>
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The Pharmaceutical Microbiology Forum Email List <[log in to unmask]>
Thu, 30 Jul 2020 16:45:26 +0000
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Hi group!

I would like to know how maintain bacteria and fungi cultures by cryogenics techniques (freezer -80°C).

My project is to reduce the amount of strain purchases per year, and I have many doubts about this.

If my original strain has 1 year of expiration, can I use it after that period using the -80°C maintenance technique? Or just in that period of validity? Because I read that I can use for about 5 years or more (USP 43 - chapter: 1117 - below).

The original sample from the national culture collection or a qualified secondary supplier is resuscitated and grown in an appropriate medium. Aliquots of this stock culture (the first transfer or passage) are suspended in a cryoprotective medium, transferred to vials, and frozen at -30° or below, until use. If stored at -70°, or in lyophilized form, strains may be kept indefinitely. These frozen stocks can then be used to inoculate monthly or weekly working cultures. Once opened, do not refreeze unused cell suspensions after culturing a working suspension. The unused portion should be discarded to minimize the risk of loss of viability and contamination of the stock."

What materials I need to have to maintain this pharmacopeial strains?

Thanks very much

Fernanda Amaro
Controle de Qualidade Microbiológico

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