Took this canning class tonight because I was hoping to learn more about technical and scientificky stuff with...
Took this canning class tonight because I was hoping to learn more about technical and scientificky stuff with canning. I unendeared myself to the instructor early on after they said that you had to use a sugar syrup to can peaches because it stopped botulism (multiple people wanted to know if you could just use water). Upon which I enquired as to the mechanism whereby it prevented the release of botulinum toxin from the spores? I mean, I actually would have liked an answer to that question because there seems to be some serious debate as to whether or not sugar is really performing any preservative function whatsoever in various foodstuffs of the long stored kind. Needless to say, I got a rather snappish and uninformative answer back.
I've found a little info by looking things up, like 38% sucrose or 22% glucose solutions inhibit growth of the spores in a lab setting. Nobody sits there and tries to calculate out an actual percent refined sugar solution, though, when they make a simple syrup to use for canning. At least, I've never seen a truly scientific analysis of home canning with this sort of info. Indeed, the instructor did not even know the bit about it inhibiting (not stopping) the growth of the spores (which are heat-resistant, hence the need to watch it when preserving food).
It's nice to pass on information and all because hey everybody does it and it's generally correct to a certain tolerance, but I would kind of like a truly specific bit of info. One thing the instructor did know was that acidic canning is better for preventing bacterial growth (i.e., botulism). C. Botulinum seems to dislike low pH. Something you can find some specifics on, although, again, I've yet to see any canning guide that points out the rough pH range of certain foods and connect that to the pH below which you are probably significantly inhibiting nasty bacteria (and/or fungi).
Where's my scientific canning guide? Grump grump grump.
I've found a little info by looking things up, like 38% sucrose or 22% glucose solutions inhibit growth of the spores in a lab setting. Nobody sits there and tries to calculate out an actual percent refined sugar solution, though, when they make a simple syrup to use for canning. At least, I've never seen a truly scientific analysis of home canning with this sort of info. Indeed, the instructor did not even know the bit about it inhibiting (not stopping) the growth of the spores (which are heat-resistant, hence the need to watch it when preserving food).
It's nice to pass on information and all because hey everybody does it and it's generally correct to a certain tolerance, but I would kind of like a truly specific bit of info. One thing the instructor did know was that acidic canning is better for preventing bacterial growth (i.e., botulism). C. Botulinum seems to dislike low pH. Something you can find some specifics on, although, again, I've yet to see any canning guide that points out the rough pH range of certain foods and connect that to the pH below which you are probably significantly inhibiting nasty bacteria (and/or fungi).
Where's my scientific canning guide? Grump grump grump.
So, how about we just pressure-can the damned peaches so we can kill the spores?
ReplyDelete(also, much specificity with regard to, say, pH, isn't actually all that helpful. Most folks don't have pH meters in the kitchen.
...even mine is in the basement.)
((I see how people think syrup-canned things are safer, though, with the whole osmotic pressure thing. Sadly, that applies rather less to botulism, which in fairness I guess I should acknowledge is a level of microbiological education beyond the average cook.))
ReplyDelete(((OK, this is getting ridiculously nested now, but: is botulinum actually released from spores, or do they have to activate and become functional bacteria again first?)))
ReplyDeleteI believe it's
ReplyDelete1. spores germinate
2. spores release bacteria
3. bacteria grow
3. bacteria release toxin
and yes, the pressure canning thing solves many problems, but they were doing a very beginner class, so just did hot water bath canning, a thing which I am disinclined to do.
As far as acid/pH, there is info on the average pH of a lot things, so you could have a rough guide table that would be plenty accurate enough, even though imprecise. Like, coca-cola and similar carbonated beverages are around a pH of 3, as is OJ which I believe roughly ranges 3-4.
I was thinking of getting the resulting pH of a batch of Stuff after chucking in lemon juice or citric acid.
ReplyDeleteThat would probably presumptively be assumed to be a good thing? I wonder about stuff like jam or sauces and such, though. That would probably require some testing out. Again, the hey everybody does it thing seems to be if you have vinegar or a fruit or something like tomatoes, it must be acidic enough. I'm betting it isn't always if you tested it.
ReplyDeleteWhen I was canning, it was the wisdom of the day that tomatoes were not acidic enough, and needed a jolt of extra acid.
ReplyDeleteYou made me look - science!
ReplyDeletehttps://foodsafety.wisc.edu/assets/preservation/UWEX_addacidtomatoes.pdf