Author Topic: Mother Culture Question  (Read 694 times)

Offline rolsen99

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Mother Culture Question
« on: January 22, 2013, 12:22:25 PM »
Out of curiosity, can a mother culture be used to make further mother culture?  Obviously, an extremely clean and sterile process would be necessary.  Is there a limit to how many times you could propagate new mother cultures?

I know in beer brewing, re-using yeast is only recommended so many times before the concern of mutations become an issue.  Is it the same thought process with bacteria?  Do commercial cheese makers continually propagate new cultures?

Offline Sailor Con Queso

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Re: Mother Culture Question
« Reply #1 on: January 22, 2013, 01:10:41 PM »
It is possible, but you risk contamination and every succeeding generation will contain mutations and different ratios of the original mix.

Here's a discussion: Mother Cultures
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Offline rolsen99

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Re: Mother Culture Question
« Reply #2 on: January 22, 2013, 01:47:21 PM »
Thanks sailor.  I don't thinks it's necessary, but was curious.

Offline Alpkäserei

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Re: Mother Culture Question
« Reply #3 on: March 01, 2013, 05:15:42 PM »
Having not read through all 6 pages of the linked post, I will ad this to the mix.

You can actually pass along a thermophilic mother culture with desirable bacteria without the need of further inoculation by starter cultures. This can be done by heat treating the culture mix in order to kill off everything, and then incubating at certain temperatures. With some understanding of how this all works, we can maintain a strong culture for generations -an entire year or even more if we freeze it periodically and re incubate.

But this requires the use of raw milk. With pasteurized milk you pretty much have to restart all the time. With raw milk, we actually lose the original cultures and replace them with wild strains. This is how we avoid the issues of mutation and so forth.

This is essentially what we do to produce our whey starters, we heat treat a portion of whey to isolate streptococcus thermophilus (not really isolate as much as make it the dominant strain) and then mix in another culture treated to isolate lactobacilli. Our ratios are not exact, but they also do not have to be. The time factors involved in lb production and the long aging terms mean that the exact populations are not critical for us.

But this is all complicated stuff, and don't do it if you don't know what you are doing. The processes we used were figured out bu generations of trial and error. It's not something you are going to just figure out in your kitchen one evening.
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