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flat sour?
Posted: Mon Oct 07, 2024 10:01 pm
by JRinPA
https://www.healthycanning.com/flat-sour/
I often leave jars in the canner after a pressure canner or steam canner session. It prevents them cooling too fast and leads to near perfect sealing rate.
I have never experienced, and hardly remember reading about, flat sour.
Has anyone actually had this happen?
Re: flat sour?
Posted: Mon Oct 07, 2024 10:14 pm
by worth1
I've never heard of it or experienced it canning with my Mom.
Together we put up a ton of green beans and carrots.
Come bush green bean season with several rows of beans at over 100 feet you've got the get a move on to keep up.
Two big canners going constantly with timers set.
No time to let stuff cool inside a canner.
As soon as they were cooled off the rings came off and I hauled them to the canned goods building.
No idea what my worthless older sister was doing.
Re: flat sour?
Posted: Mon Oct 07, 2024 11:17 pm
by Whwoz
I seem to recall this from my Microbiology student days but have not experienced it personally. Going by the list of bacterial given in that link, it would be caused by underprocessing of the food. Those bacteria should be killed by standard conditions designed to kill Clostridium botulinum spores which are slightly more resistant to heat than most Bacillus spp.
Either that or the food was highly contaminated with a heavy bacterial load to start. Highlights the importance of preserving only clean foodstuffs.
Re: flat sour?
Posted: Tue Oct 08, 2024 1:59 am
by worth1
I'm not microbiology expert but I was flummoxed when I read that these bacteria or their spore survived a pressure cooker.
Yes there are bacteria that survive extremely harsh conditions around hot thermal vents black smokers deep on the ocean floor under extreme pressure and heat but they aren't up here where we are.
Re: flat sour?
Posted: Tue Oct 08, 2024 2:47 am
by Whwoz
A lot of the deep sea bacteria, strictly speaking they should be called Archea, are actually older than those that form spores and can't do so. The highest temperature that I am aware of archea growing to is 113C/235F, personal best is 105C/221F.,many years ago now.
The sporeformers tend to be soil based and hence are really only a problem when food is soil contaminated. Standard sterilising conditions 121C/15 minutes at STP are aimed at reducing the microbial spore load by 90%. Tests are conducted commercially for every new process to determine safe operating conditions.
Re: flat sour?
Posted: Mon Oct 21, 2024 11:08 am
by worth1
Whwoz wrote: ↑Tue Oct 08, 2024 2:47 am
A lot of the deep sea bacteria, strictly speaking they should be called Archea, are actually older than those that form spores and can't do so. The highest temperature that I am aware of archea growing to is 113C/235F, personal best is 105C/221F.,many years ago now.
The sporeformers tend to be soil based and hence are really only a problem when food is soil contaminated. Standard sterilising conditions 121C/15 minutes at STP are aimed at reducing the microbial spore load by 90%. Tests are conducted commercially for every new process to determine safe operating conditions.
I forgot to comment on this.
I read some time ago that the US government testing facilities didn't have the funds to do research for more modern standards and things to preserve.
We're basically stuck in I think 1930s research.
It took years for them to drop the safe temperature for pork and poultry.
Me being me did my own research and came up to the same results.
Some from reading books on safe preservation of salami and other meats.
Re: flat sour?
Posted: Mon Oct 21, 2024 7:30 pm
by Shule
I've never heard of flat sour, but it's reassuring that it's not poisonous.