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ruawakeyet


Registered: 05/03/21
Posts: 1,862
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28050336 - 11/14/22 09:55 AM (1 year, 2 months ago) |
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Quote:
p9hu7 said: Should the standard cycle be sufficient to sterilize each load, I have no reason at this point to believe that the cycle will fail at this point, I think it will be interesting and beneficial to first determine the minimum cycle required to sterilize a 1L grain master rather than move onto grain bag's, initially.
Reducing the cycle by 30 mins to begin. I will choose only one grain for this as the cycle appears to have the same outcome despite grain choice (should all the grains continue to pass). I will also use 4 x 1L jars/ cycle (same grain)to determine the efficiency, perhaps some will sterilize while others fail.
1 hour at 15psi with a 10 mins vent. If the cycle is verified at 1 hour I will drop by 10 mins until it fails.
If the cycle fails I will increase by 10 minute increments until verification is achieved.
We will then have the minimum parameter for cycle effectiveness.
All the test parameters in this thread are extremely interesting and informative, but I have been eagerly awaiting the results to the test outlined above, as well as the small pressure cooker test. I will continue to wait anxiously. Thank you for this data!
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Rusty2096
rah rah raw in Lady gaga



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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28050337 - 11/14/22 09:56 AM (1 year, 2 months ago) |
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Oats + IP = guaranteed success
-------------------- Currently looking for nothing. You guys who sent me stuff are straight up awesome!. We don't own things - things own us. Semi-solid liquid culture (SSLC)
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rumfor69
Bodhicitta Cultivator



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Re: Autoclave Validation and Load/Cycle Verification [Re: Rusty2096] 1
#28050466 - 11/14/22 10:57 AM (1 year, 2 months ago) |
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I'm curious if longer vent times are required for more jars or bags in a big cooker like the AA941. It's a large vessel, then lots of jars or bags in it, and all have their air in them. I would think it'd take more than 15min to get all those individual containers to heat up and vent and then vent out the PC.
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Stipe-n Cap


Registered: 08/04/12
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Re: Autoclave Validation and Load/Cycle Verification [Re: rumfor69] 1
#28050550 - 11/14/22 11:38 AM (1 year, 2 months ago) |
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More is more with sterility so even though you may be able to get away with less I would always recommend longer pc cycles and vent times for redundancy if nothing else.
Larger vessels like my 75x always get 30 min vent times although I started with 20. These AA sterilizers recommend pulsing to purge which I don't really trust for grains.
I prefer lomger venting to allow for all surfaces both internal and external to reach even working temperatures.
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rumfor69
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap] 2
#28050559 - 11/14/22 11:45 AM (1 year, 2 months ago) |
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So awesome thank you p9! I was thinking the same thing lately. I've been having bacterial issues in jars for yrs not matter what I've done. Finally I decided to overkill the vent times. I figured what the hell this aa941 holds a ton of water and I use weights on the jiggler so I started venting 30-40mins with that same idea you just said in mind and it's instantly having an effect.
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Stipe-n Cap


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Re: Autoclave Validation and Load/Cycle Verification [Re: rumfor69]
#28050564 - 11/14/22 11:47 AM (1 year, 2 months ago) |
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Makes perfect sense.
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rumfor69
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap] 1
#28050610 - 11/14/22 12:06 PM (1 year, 2 months ago) |
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Taking this theory a little further I also think that vent times will vary slightly for all of us depending on cooker model do to it's size, shape, and thickness. Variances in the heat source like btu size, burner size, fuel efficiency, flame quality, jar glass thickness. Atmospherical effects like barometric pressure, elevation, ambient temperature, grain temp when loading, on and on
Sure all these things are small but a lot of small things add up. And I think this is the answer as to why so many are having bacterial issues even with flawless dishes and perfectly good working flowhoods. Some standard 10-15min vent isn't going to work the same from person to person, and could even not work from run to run with the same person and gear.
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Stipe-n Cap


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Re: Autoclave Validation and Load/Cycle Verification [Re: rumfor69] 2
#28050632 - 11/14/22 12:17 PM (1 year, 2 months ago) |
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Yes it sounds perfectly reasonable that as any variable or set of variables change there will be fluctuations in efficiency, to what extent is ytbd however this is why overkill is preferable to dogmatic adherence the known minimum effective cycle.
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redcrow

Registered: 03/25/22
Posts: 384
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap] 1
#28051331 - 11/14/22 05:35 PM (1 year, 2 months ago) |
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p9,
Thanks so much for you efforts here. You are The Man!! You've obviously put a lot of time and effort, not to mention serious coin, into this investigation, and the results are both enlightening and useful.
Seriously. To have our common practices confirmed (or denied) by well designed scientific testing is a treasure. There are a lot of techniques that people get dogmatic about when all they've proven is that those practices work for them in their environment. The old "anecdotal evidence" logical fallacy gets way too much exercise when discussing the merits of one method or another.
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Stipe-n Cap


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Re: Autoclave Validation and Load/Cycle Verification [Re: redcrow] 2
#28051371 - 11/14/22 06:02 PM (1 year, 2 months ago) |
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There's been two schools of thought regarding endospores; some folks firmly believed that it wasn't possible to truly sterilize grains, that we were at best providing a short window of opportunity for the mycelium to take hold, something like hyper pasteurization.
While others argued that due to their own personal experience they believed that endospores were completely destroyed for whatever reason(s), the issue was that neither side had any evidence to point to to support their claim. Folks argued that despite pharmaceutical sterility assurance the loads we subject our pressure cookers to are too different to be able to confidently apply that data to our particular circumstances.
I'm surprised that nobody ever took the time to run the verification, but I'm more than happy to do it.
Hopefully this will help in some way.
Oats have been hydrated for the final baseline cycle verification, millet has been prepped to run validation on the instantpot.
I'll be running both tomorrow, too tired this evening.
Edited by Stipe-n Cap (11/14/22 06:09 PM)
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Rusty2096
rah rah raw in Lady gaga



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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28051383 - 11/14/22 06:11 PM (1 year, 2 months ago) |
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-------------------- Currently looking for nothing. You guys who sent me stuff are straight up awesome!. We don't own things - things own us. Semi-solid liquid culture (SSLC)
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redcrow

Registered: 03/25/22
Posts: 384
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28051432 - 11/14/22 06:41 PM (1 year, 2 months ago) |
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Quote:
p9hu7 said: There's been two schools of thought regarding endospores; some folks firmly believed that it wasn't possible to truly sterilize grains, that we were at best providing a short window of opportunity for the mycelium to take hold, something like hyper pasteurization.
Given the enormous pressure and temperature and toxic chemicals at the bottom of the Marianas trench, where a whole ecosystem thrives, I'm inclined to side with those folks. That as fragile a phenomenon as life is so durable is beyond amazing
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Stipe-n Cap


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Re: Autoclave Validation and Load/Cycle Verification [Re: redcrow] 5
#28051437 - 11/14/22 06:44 PM (1 year, 2 months ago) |
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Well the data is in, 90 mins at 15psi with a 10 min purge positively sterilizes biological indicators filled with 106endospores from Bacillus stearothermophilus.
Should you run your cycle correctly your grain is 100% sterile. There is no doubt.
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Egon_Spengler
Ever lurkin never workin



Registered: 04/02/22
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap] 2
#28051457 - 11/14/22 06:56 PM (1 year, 2 months ago) |
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Quote:
p9hu7 said: Well the data is in, 90 mins at 15psi with a 10 min purge positively sterilizes biological indicators filled with 106endospores from Bacillus stearothermophilus.
Should you run your cycle correctly your grain is 100% sterile. There is no doubt.
Just for clarification, the above is regarding baseline for oats in a pressure cooker? Or this is the results of testing the millet in an instant pot?
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Stipe-n Cap


Registered: 08/04/12
Posts: 7,623
Loc: Canada
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Re: Autoclave Validation and Load/Cycle Verification [Re: Egon_Spengler] 1
#28051469 - 11/14/22 07:07 PM (1 year, 2 months ago) |
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Have you not read the OP?
I have not run the validation test on the instant pot yet, I just bought it today.
I have ran cycle verification for: wheat, millet, and corn; oats will be run tomorrow. Baseline refers to the verification process for the standard time temperature cycle set for 90 minutes at 15psi. All biological indicators have sterilized when exposed to the standard cycle, I do not forsee oats failing.
You should really read before asking, it seems exceptionally lazy.
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Egon_Spengler
Ever lurkin never workin



Registered: 04/02/22
Posts: 2,294
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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap] 3
#28051499 - 11/14/22 07:28 PM (1 year, 2 months ago) |
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I had, but itβs been a while. Thank you for the clarification.
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rumfor69
Bodhicitta Cultivator



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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28051867 - 11/14/22 11:02 PM (1 year, 2 months ago) |
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Quote:
p9hu7 said: Should you run your cycle correctly your grain is 100% sterile. There is no doubt.
This being the million dollar statement regarding what p9 and I were talking about a few posts ago
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Stipe-n Cap


Registered: 08/04/12
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Re: Autoclave Validation and Load/Cycle Verification [Re: rumfor69] 2
#28053511 - 11/15/22 07:49 PM (1 year, 2 months ago) |
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Some very interesting preliminary results with the instant pot. I ran a 1L jar of millet for 3 hours on max pressure, the biological indicator is now in the incubator and will be ready tomorrow evening.

Here's the deets on pressure:

There's not much head space in the 6 quart so I had to lay it on it's side.
1x BI ampoule 1x chemical indicator strip

The BI has it's own chemical indicator strip which registered a positive sterilization:

And the chem strip itself has also registered positive sterilization, though just barely:
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SirPsycho
Purple Belt in Google-Fu



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Re: Autoclave Validation and Load/Cycle Verification [Re: Stipe-n Cap]
#28053523 - 11/15/22 07:52 PM (1 year, 2 months ago) |
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Are you also gonna run the thermometer or will you consider the ampoule enough of a verification?
--------------------
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Stipe-n Cap


Registered: 08/04/12
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Re: Autoclave Validation and Load/Cycle Verification [Re: SirPsycho] 1
#28053529 - 11/15/22 07:53 PM (1 year, 2 months ago) |
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Amp is enough, no room for the thermometer. The BI is considered to be the benchmark in validation testing so it is a stand alone, the thermometer was just a failsafe.
Oats are being cycled in the presto as we speak.
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