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KrissKross
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Registered: 08/25/04
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Ultra-high temperature processing (UHT) pasteurization
#7590149 - 11/03/07 03:11 AM (16 years, 2 months ago) |
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I was reading about pasteurization on Wikipedia. Apparently there are two methods of pasteurization that are generally used to treat food products, milk being the prime example.
The most common method is called "high temperature/short time (HTST)" AKA flash pasteurization. It involves temperatures of about 160 F for a duration of about 15-20 seconds. OF course this is in the same temperature range that we use to prepare bulk substrates and of course is not high enough to achieve sterilization, even after very long durations (as far as I know). Obviously for a substance such as manure or straw the time needed is much longer than for milk or juice.
The other method is called "Ultra-high temperature processing (UHT)" and is applied for about "1-2 seconds, at a temperature exceeding 135°C (275°F), which is the temperature required to kill spores in milk." The article goes on to state that UHT is also used on such semi solid foods as: yogurt, soups, and stews.
http://en.wikipedia.org/wiki/Pasteurization http://en.wikipedia.org/wiki/Flash_pasteurisation http://en.wikipedia.org/wiki/Ultra-high_temperature_processing
As a side note I have to say I was disappointed that the articles make no mention of using pasteurization in mushroom cultivation or other forms of biological work.
Now upon reading this the question naturaly forms in my head; Can bulk substrates be heated at higher temperatures (>170 F) for shorter durations and achieve the same effect as pasteurizing at lower temperatures for a longer duration? Has anyone ever tried this? If grains must be PC'd for 1-2 hours, would that mean that only Pcing for 5-15 minutes would have the same effect as pasteurization, and if so does that mean that I could perform UHT pasteurization of Bulk substrates using my PC?
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greys
OTD Sergeant at Arms



Registered: 07/16/06
Posts: 44,923
Loc: nunya
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: KrissKross]
#7592557 - 11/03/07 09:03 PM (16 years, 2 months ago) |
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i have thrown composted cow manure, vermiculite and even shredded straw in quart jars and pc'd it for 15-30 minutes at 15 psi before. it worked well. The original reason i did it was because it was so effin cold outside one winter the damn turkey fryer setup was taking forever (fuel probably gelled in the cylinder) so out of desperation i just scooped everything into widemouth quarts and pcd instead of boiled. i have a fair sized pc so this worked ok for me.
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KrissKross
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: greys]
#7593084 - 11/03/07 11:32 PM (16 years, 2 months ago) |
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Sweet deal. How full do you fill the jars? Do you put something over the mouth of the jars or just leave it open?
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MotorCityMadman
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Registered: 10/02/06
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: KrissKross]
#7610401 - 11/08/07 10:02 AM (16 years, 2 months ago) |
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I think you'd have to liquefy your substrate for this to work...
I assume that this UHT processing is done by passing the milk through a tube running through a hot bath of something...
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shroom_ninja
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: MotorCityMadman]
#7611213 - 11/08/07 01:25 PM (16 years, 2 months ago) |
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correct, and UHT would require some very seriously heat-resistant materials. Glass is out of the question, and given such short heat/cool times, pyrex might even crack. and yeah, you can't really heat any type of bulk to that temp quickly unless you bottleneck somehow, so that you get direct, or near-direct contact to the heat source evenly throughout your mixture. This means it would have to be near-liquid, and pumped quickly.
and another concern would be over-heating your grain or food source. you can, and probably will, simply burn it. I can't help in any detail with that, however.
In any case, I can't really see any non-industrial solution here being more cost or time efficient than using conventional methods for bulk substrate.
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KrissKross
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: shroom_ninja]
#7617277 - 11/09/07 11:56 PM (16 years, 2 months ago) |
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So if I were to PC hydrated horse poo in quart jars, for 15 minutes @ 15 PSI, what the effect of that be? Would it kill more or less of the microbes than pasteurization? Would it be too close to sterilization? Realy what im proposing here is to heat it hotter than 170F, possibly to around 250F, and leave it there for 5-10 minutes or something,I dont see why that would be a problem.
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MotorCityMadman
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Re: Ultra-high temperature processing (UHT) pasteurization [Re: KrissKross]
#7625052 - 11/12/07 10:14 AM (16 years, 2 months ago) |
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You'd probably wind up sterilizing (or almost sterilizing) the medium touching the glass, and doing little or nothing to the medium in the middle of each jar.
Maybe you could pack everything into 100 or so test tubes and that would allow sufficient surface area to volume ratio to achieve this, but that would be such a waste of time and effort as to make a person wonder "why not just pasteurize the regular way?"
short answer: just pasteurize using established easy methods.
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