Bacillus Subtillus culture

Enigl enigl at aol.com
Mon Nov 27 22:29:19 EST 1995


In article <30B2879A.54A9 at smartnet.net>, dwimmer at smartnet.net writes:

>4. Spin down the stuff to get a nice thick tan paste.
>5. Bring up to about 50mL with sterile saline.
>6. Heat shock at about 60dC for a half hour or so. Store in the 
>fridge.
>This will give a culture containing about 8 logs per 0.1mL and 
>should last at least a couple of years.

The above sounds very good to me.  One thing I'm surprised about is the
lack of any one using isopropyl alcohol preservation.  It seems to be
"standard" practice in my industry for storing sterility testing spores
for hydrogen peroxide sterilizing agents: 

We cultivate the spores on solid plate count agar medium in cake pans at
30-35 C.  Plate count agar seems to work just fine with over 90% spores in
about a week.  Then we scrape off the spores with 70% isopropyl alcohol. 
That kills off most everything except the spores.  Storage in 70% IPA at
2-8 C has been very good with only a one log reduction in ten years.  The
scraped suspension is 10^10 to 10^11 CFU/mL (a thick moist, IPA paste).  

Our method eliminated the centrifugation step and the heat shock step.


Davin C. Enigl
Send Internet e-mail to: enigl at aol.com
Send AOL e-mail to:  Enigl

November 27, 1995
7:22 pm



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