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BeefSupremeJr
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Re: PC'd Grain - Life Span? [Re: Mateja]
#25845589 - 03/01/19 11:03 AM (5 years, 29 days ago) |
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Just had a jar of oats that was 11 days old contam. Shook it and it was the brown mush. Smells like barbecue?
Second jar of oats on the same run to contam. 2hr pc cycle at 16psi.
I find it doubtful that my lids are faulty. Just saying. I have a whole new set of lids and if this happens again the next run, Iβm quitting oats.
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: Pinback]
#25845609 - 03/01/19 11:21 AM (5 years, 29 days ago) |
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Quote:
Pinback said:
Quote:
bodhisatta said: To think a grain jar is 100% completely sterilized in 90-120m at 15psi is blasphemy to me. And should be to anyone whos done some research on endospores and sterilization. It would probably take over 8 hours at pressure to ensure grain got sterilized in actuality.
Why do you believe this?
See my other posts in this very thread
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Pinback
Stranger
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25845744 - 03/01/19 12:24 PM (5 years, 29 days ago) |
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Thanks, but I don't see where you got 8 hours from. Microbiological waste (plates, solid media, cloth, tools, etc.) is routinely sterilized, in bags, in much shorter time.
If I would make petri dishes using semi-ground rye, and they didn't contaminate after two weeks, would that change your mind?
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JHOVA
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Re: PC'd Grain - Life Span? [Re: Mateja]
#25845752 - 03/01/19 12:30 PM (5 years, 29 days ago) |
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Absolute statements either apply universally or they arent absolute. Nothing wrong with nuance.
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π° πΏ
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gizmodo
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Re: PC'd Grain - Life Span? [Re: JHOVA]
#25845766 - 03/01/19 12:42 PM (5 years, 29 days ago) |
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You little bastards.
-------------------- One must be mindful to maintain their balance on the slippery earth. Bod's Comprehensive Agar Resource Gizmodo's Market Stall Say No To Grow Kits
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Mateja
Registered: 07/14/16
Posts: 7,948
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Re: PC'd Grain - Life Span? [Re: bodhisatta] 2
#25845889 - 03/01/19 01:40 PM (5 years, 29 days ago) |
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God damn it now I have even more questions. These Bacillus are apparently mostly found in dirt/soil around the surface level and are present on most vegetation. 1g of human poop apparently contains thousands of these. There should theoretically be a bunch of them present in BRF as well since rice is vegetation and it comes from soil and is produced in open air. Bacillus spores are basically everywhere and must therefore end up in all sorts of organic material?
Quote:
bodhisatta said: To think a grain jar is 100% completely sterilized in 90-120m at 15psi is blasphemy to me. And should be to anyone whos done some research on endospores and sterilization.
So what about my GWA plates? Would you consider them not sterile as well because they were PCd for only 15min at barely 5-10PSI on the ever degrading IKEA PC?
If I've understood you correct it's 'blasphemous' to believe that 100% of endospores are killed in 15min at 15PSI of 'effective heat cycle'. To me it sounds like you're inevitsbely implying also that a GWA media can not be sterilized, is this so and if not could you expand on this a little in case I've missed something essential?
Id like your opinions and ideas as well Stare if you haven't been bored to death by now lol your posts are always well written and good explanations and good info relevant to the topic didcissed, that's why I always read all your posts I catch in MC. As you can see now I became curious about GWA and endospores, its just the way I am, want to know how is what and why. I don't agree with everything bod does or says or you or many other and God forbid if anyone should agree with everything I say and do. Most of us here are characters with strong personalities but I like how we can still keep it cool and have productive discussions without rendering our discussions pointless. I believe several posters in this thread have learned good stuff today. Peace
But yall please shed some light for me about GWA endospore sterilization?
-------------------- Cakes inside Water Tub
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: Mateja] 2
#25845917 - 03/01/19 01:51 PM (5 years, 29 days ago) |
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Liquids are extremely easily sterilized unlike grain. anything but liquids and surgically clean stainless steel instruments are a pain to sterilize. Grain water should take 15m @ 15psi.
A bioburden of 10,000,000 endospores in 500ml liquid would die to a survival chance of 1 in 10,000,000 with 15m @15psi. Now grain with a bioburden that's the same might take all day
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25845927 - 03/01/19 01:56 PM (5 years, 29 days ago) |
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It's not really a question of the endospores its a question of what material you're sterilizing. The endospores are there.
My theory about BRF is that the endospores are there they just cant do any harm so steaming works to kill all vegetative growth in cakes and that's sufficient
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Pinback
Stranger
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846000 - 03/01/19 02:34 PM (5 years, 29 days ago) |
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Quote:
bodhisatta said: Liquids are extremely easily sterilized unlike grain. anything but liquids and surgically clean stainless steel instruments are a pain to sterilize. Grain water should take 15m @ 15psi.
A bioburden of 10,000,000 endospores in 500ml liquid would die to a survival chance of 1 in 10,000,000 with 15m @15psi. Now grain with a bioburden that's the same might take all day
If the endospores have a D121C of about 2 min, then yes. It is the same for grain, only that the slower heat transfer requires a longer time to reach 121 C.
As a general note, around 15 years ago, most people here sterilized grain for 1 hour, with good results. I don't know when that changed to recommend longer times.
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Mateja
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846001 - 03/01/19 02:34 PM (5 years, 29 days ago) |
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Quote:
bodhisatta said: Liquids are extremely easily sterilized unlike grain. anything but liquids and surgically clean stainless steel instruments are a pain to sterilize. Grain water should take 15m @ 15psi.
A bioburden of 10,000,000 endospores in 500ml liquid would die to a survival chance of 1 in 10,000,000 with 15m @15psi. Now grain with a bioburden that's the same might take all day
"Grain water should take 15min at 15PSI (~121C)" this part of the sterilization is what I call 'effective heat cycle' clocking from the point you've estimated that sufficient heat has reached out to all spores in the liquid media/grain jar.
As you mentioned it's much easier to heat an endospore in a liquid than one inside a wheat berrie that consists of ~75% water weight. Due to the lower density and pourus structure inside the grain, considerably higher temps than 121C are required to be able to heat the center of every grain to at least 121C. Or like you mentioned you would need much longer sterilization cycle to achieve the end goal of at least 15min of 121C of effective heat cycle.
But..
Here comes a honest question from me just trying to see if I'm on the right path of understanding all of this. So:
Let's say you are fairly sure that an 8h cycle on 15 PSI will deminish the bioburden inside grain jars down from 10 000 000 to 1. But what if you sterilized the grain at ~80 PSI, would those temps cut down the heat duration cycle to around 2-3h? You have an estimation off the hip for this?
Also I think I understand what you're saying about that I can't compare liquids and grain cause it's too different that simply increasing heat and duration 'linearly' won't guarantee every cubic mm in the grain will get cooked because of more complex variables in the composition of the grain/type of grain and prep. I could be wrong tho. (I hope you can make sense of my last statement even tho I use concepts and dialectic in a little weird way cause I'm not totally rested.)
-------------------- Cakes inside Water Tub
Edited by Mateja (03/01/19 02:39 PM)
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Pinback
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Re: PC'd Grain - Life Span? [Re: Mateja]
#25846009 - 03/01/19 02:40 PM (5 years, 29 days ago) |
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Quote:
Mateah said: Let's say you are fairly sure that an 8h cycle on 15 PSI will deminish the bioburden inside grain jars down from 10 000 to 1. But what if you sterilized the grain at ~80 PSI, would those temps cut down the heat duration cycle to around 2-3h? You have an estimation off the hip for this?
This can be modelled by a so-called z-value for the organism. But there really is no need for those temperatures and times...
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JHOVA
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Re: PC'd Grain - Life Span? [Re: Mateja]
#25846011 - 03/01/19 02:42 PM (5 years, 29 days ago) |
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Matea do you own a pc that goes to 80 psi? How about 300 psi? What about 10,000 psi? The tools we have is a regular pc that can go up to 20 with a few quarters. Anything more is an arbitrary # pulled out the aether for practical purposes.
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π
π° πΏ
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Mateja
Registered: 07/14/16
Posts: 7,948
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Re: PC'd Grain - Life Span? [Re: JHOVA]
#25846036 - 03/01/19 02:57 PM (5 years, 29 days ago) |
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@Pinback
Thanks for being European and that the link was in Celsius Fahrenheit has been giving me migraine lately, I can handle cups, ounces, feet and inches but my cpu is full for the moment when it comes to measurements in Hollywood language.
Quote:
JHOVA said: Matea do you own a pc that goes to 80 psi? How about 300 psi? What about 10,000 psi? The tools we have is a regular pc that can go up to 20 with a few quarters. Anything more is an arbitrary # pulled out the aether for practical purposes.
My PC goes to 20 PSI, but autoclaves go higher and I might be able to get access to one or two soon. I could probably do something valuable by experimenting with sterilizing a bunch of jars at much higher Temps but not so high that they compromise the quality of the grain. But yes 80PSI was pulled out of gods beard for practical reasons
-------------------- Cakes inside Water Tub
Edited by Mateja (03/01/19 02:58 PM)
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: JHOVA]
#25846052 - 03/01/19 03:09 PM (5 years, 29 days ago) |
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Quote:
JHOVA said: Matea do you own a pc that goes to 80 psi? How about 300 psi? What about 10,000 psi? The tools we have is a regular pc that can go up to 20 with a few quarters. Anything more is an arbitrary # pulled out the aether for practical purposes.
If you removed the safety blowout plug any PC would easily hold 80psi. I don't suggest it tho and you would burn the grains.
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: bodhisatta] 2
#25846084 - 03/01/19 03:27 PM (5 years, 29 days ago) |
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planctonic(yes spelled right google will change it on you) micro-organisms are extremely easy to kill. Biofilms are a different ball game entirely. Planktonic means single cells disperse usually in liquid.
I do believe i once read that biofilms can make bacteria 1000x harder to sterilize than planctonic bacteria. Some of these biofilms contain endospores protected at the core. Bacteria in biofilms produces extracellular signaling chemicals that let subsets of the bacteria in the film do specific jobs like become more hydrophobic. Stranger yet is bacteria produce plasmids that float in the extracellular matrix in a biofilm these can enter other bacteria and change their DNA to perform specific tasks. So bacteria in a film behaves more like a multicellular organism than it resembles the single individual.
Poor pre-cleaning of medical instruments before sterilization is a big cause of failed sterilization. Think about trying to scrub the bioburden off of the inside of grains, you cant
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BeefSupremeJr
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846100 - 03/01/19 03:33 PM (5 years, 29 days ago) |
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Mateja
Registered: 07/14/16
Posts: 7,948
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846115 - 03/01/19 03:41 PM (5 years, 29 days ago) |
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Quote:
bodhisatta said: planctonic(yes spelled right google will change it on you) micro-organisms are extremely easy to kill. Biofilms are a different ball game entirely. Planktonic means single cells disperse usually in liquid.
I do believe i once read that biofilms can make bacteria 1000x harder to sterilize than planctonic bacteria. Some of these biofilms contain endospores protected at the core. Bacteria in biofilms produces extracellular signaling chemicals that let subsets of the bacteria in the film do specific jobs like become more hydrophobic. Stranger yet is bacteria produce plasmids that float in the extracellular matrix in a biofilm these can enter other bacteria and change their DNA to perform specific tasks. So bacteria in a film behaves more like a multicellular organism than it resembles the single individual.
Poor pre-cleaning of medical instruments before sterilization is a big cause of failed sterilization. Think about trying to scrub the bioburden off of the inside of grains, you cant
Read today that Bacillus can die and still germinate if it's DNA is intact.
-------------------- Cakes inside Water Tub
Edited by Mateja (03/01/19 03:41 PM)
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bodhisatta
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Re: PC'd Grain - Life Span? [Re: Mateja] 2
#25846118 - 03/01/19 03:42 PM (5 years, 29 days ago) |
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What's die really mean for a single celled bacteria when you can get it wet and it puts itself back together. Some of these signals that bacteria make during biofilm formation tell a subset of the film to protect their DNA and even further tell some bacteria to start forming extra tough endospores with more dipicolinic acid. As well some are forming with moderate levels and low levels. So that there's endospores that are super protected from DNA damage and some that are more ready to spring into action. Many people seem to think endospores only form in dire conditions. That just pushes the amount formed to a higher %. Bacteria is always maximize its survival chances. Some subset of the population of a film is making spores at a slow rate during optimal conditions and during dire conditions that proportion grows larger. This is why tyndalization doesn't really work and there's other reasons too like Never being able to germination every spore during the in between sterilization phases anyway.
I like to think of a biofilm in or on a grain as a fortified castle with a modern bank vault inside and inside the vault are people wearing the same gear that the people who work with molten steal do and if they die so long as not all their DNA is burnt to a crisp they can rebuild and come back to life.
So yea much different than sterilizing liquid
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BeefSupremeJr
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846153 - 03/01/19 04:02 PM (5 years, 29 days ago) |
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Quote:
bodhisatta said:
I like to think of a biofilm in or on a grain as a fortified castle with a modern bank vault inside and inside the vault are people wearing the same gear that the people who work with molten steal do and if they die so long as not all their DNA is burnt to a crisp they can rebuild and come back to life.
So yea much different than sterilizing liquid
That canβt be unseen
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Mateja
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Re: PC'd Grain - Life Span? [Re: bodhisatta]
#25846156 - 03/01/19 04:03 PM (5 years, 29 days ago) |
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Organismgasm
I knew from long ago they could monitor their environment and adapt while dormant, but I had no clue they were this komplex and interesting.
Aspergillus and Trich spores are like the Flintstones car and Bacillus is Transformers truck.
-------------------- Cakes inside Water Tub
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