28 replies to this topic

[llama]

I was paging through a microbiology text today, and noticed a section on what is termed fractional sterilization. The technique is used to destroy bacterial endospores without requiring temperatures above 100C. When working with grain jars, this is often accomplished similarly by soaking them overnight to allow germination before sterilization. I know several of you have had success with just steaming, but this seems to be more of a surefire way for those without PCs or for those wishing to sterilize non-heat-resistant plastic containers. The downside is that it requires patience, or at least planning.
First, steam the material for 30 minutes. Incubate at 37C for 12 to 24 hours to allow bacterial germination. Repeat steaming and incubation steps, and then steam again for 30 minutes after the second incubation period.
That's it. Hopefully someone finds this useful.
Cheers,
Llama

[Hippie3]

i'd steam at least 1 hour, maybe even 2 hrs
each time
and i've been told to steam
three times on three successive days

[tripinstein]

I have wanted to use WBS for a while but not having a PC has prevented me from using it. So I tried a methoud of bleach sterilization and so far no problems.

Here is what I did: I took the WBS I was going to use, put in a bowl and put in 200ml of bleach with every 3 cups of water and let the seed soak stirring occasionaly for about an hour. Then I drained and rinsed the seed. Next I brought the seed to a slow boil in a pot of water, and when it started boiling I let it do this for 10 mins. Afterwards, I drained and loaded into some jars, and sterilized by boiling for an hour and a half. Let them cool and then innoculated with an LC.

That was just a few days ago and the growth is looking pretty good and so far no sign of contams. I did this to avoid fractional sterilization. So far so good! Anyone tried this before? Any comments?

[blackout]

Great. I was thinking of something similar a while back, just using bleach with no heat. I would have let the seed soak in bleach longer. But if it works and is repeatable then you are onto a winner.

agar at the shroomery said he got growth on ground WBS PF cakes that were microwaved for only 4-6minutes.

[tripinstein]

I don't like using the microwave myself, but that is impressive. If bleach kills everything, then the seed would really only need to be soaked long enough for all the seeds to come into contact with it a few minutes, plus I used a strong solution of bleach/water. So far all is well, if they colonize 100% then I'll let everyone know. This might help those of us less fortunate who don't own a PC. The growth has been explosive overnight! This stuff colonizes fast.

[blackout]

I questioned the killing of endospores in 4-6mins. He put it down to it being ground up so they were not insulated against heat. I have unsucessfully sterilized wet flour in the microwave after a 60minute heating.

The bleach may be able to penetrate the small WBS grains.

[blackout]

What grains have you tried freakachino?
the best is RGS except it is so damn expensive.

[tripinstein]

Thanks freakachino. Since people use bleach to pasturize bulk subs, I figured it could be done with grains as well. I still used the boiling sterilization though, so the real test would be a bleach only sterilization and see if that worked.

[AlienTouch]

I do believe bleach breaks down the grain so it soaks more water up.

:crazy1:

[blackout]

RGS was another I figured would have a good chance. And I think I read somewhere that RGS is better at not growing contams than some other grains.

That is strange. I had heard it had a high endospore count. Yet many say they get away with pasteurising straw which has heads in it. Those straw heads look like RGS.
I like RGS for fractional sterilization in the microwave. It does not explode when heated in excess water like rye/wheat etc. So you can cover it totally in water and heat it for a long time in the microwave driving off water as you go. The excess water leads to an even heating with no hot/cold spots in the jar, since water is so conductive. I have microwaved it down until it was completely dry again, then added moisture back as LC. This will lead to rapid colonisation with no need for shaking of the jars, leaving little time for any contams to take hold.

[tripinstein]

The jars are still crusin' along well, no contams just good thick growth. Just in case anyone else was wondering.

If anyone has given this a shot, I would strongly suggest the boiling after the bleach soak. I tried some jars with a bleach soak and rinse and then to the jars and I think the bleach killed the tissue from my LC because I have yet to see anything good or bad. Could have not rinsed long enough though.

Sorry I cannot post pics. My birthday is on the 17th of this month, and I think my chick got me a new camera (been hinting for a while)!! Hope so cause I want to post my successes on a few projects I have going, like this one.

[blackout]

The boiling after the bleach will not just rinse the grains well, it will degrade the bleach turning it into salt and chlorine gas. Since it is boiling it will drive off the gas well and if you are using lots of water the salt will be sell diluted.
This bleaching would probably work well with RGS with its thin open structure.

[tripinstein]

All my jars are just about finished colonizing and this is the eighth day. All is still going smoothly.

[420j4u]

Theoretically, Could fractional sterilization work in bulk?
If a person were to get thick plastic and an iron with a towel and make a Myco bag type thing. I'm talking a Myco bag that eats other myco bags for dinner and shits ethenal.
One that would fit 50lbs of popcorn.
All done in a 55 gallon drum of course. You would need a cherry picker to hang it, and a floor jack to kneed it.
But could it work?
Or, some 55 gallon drums have a metal ring that seals the cover on tight. Could a person add a pressure guage to it and call it a 220 qt home made pressure cooker.
Or one heck of a home made Myco-bomb, one of the two.

You could use a shovel...
Build Mount' Spawn, and put a little mycotopia flag on top.

[OZ]

yeah if you could build it, im sure it would work

[OZ]

i didnt mean the diy pressure cooker, i meant the fractional sterilization with bulk amounts of grain..
yeah a diy PC is not a good idea