What happens if my canned foods freeze?

Precautions if I expect that to happen?

Nothing. I keep home canned and store bought canned goods at my trapline all the time. Doesn't hurt it at all. Botulism spores dont grow at temps below 50 degrees so keeping canned food in a cool place is preferable. I do check the seals before eating but they are always fine.

The freezing causes expansion of the jars or cans,,and can ruin the canned foods

since we're on the subject...

I see most of the larger canners shouldn't be used on glass-top electric stoves...can they be used on propane-fired turkey fryers?

The manufacturer has a weight limit for glass tops. I checked for my GE and the limit was 70 pounds...not many canners weighing 70 pounds, at least not the All-American that i use. Having said that, i still put it on a turkey fryer just to be safe. Seems easier to keep a constant temp with a flame rather than electric elements.

Just make sure you boil everything for 10 minutes after you open it to denature the toxin. Pretty sure that's the only thing that kept a bunch of people from dieing in the old days with canned food. I know my grandparents would boil and cook the heck out of everything had to make sure it was good and cooked lol. In all seriousness when in doubt throw it out. Seen an article the other day where a Russian couple ate some bad pickles from grandma and ended up dead from botulism. It's not the bacteria that get you it's the toxin they produce to make the environment uninhabitable to other pathogens. They are poor competitors so they have to poison everyone else to win.

Nothing will happen should the contents freeze as they are sterile and sealed. HOWEVER, should the expansion of the frozen contents crack or breach the seal then you have potential entry of dangerous microbes. Aesthetically freezing of certain foods can effect the taste or texture.

I would think sealed metal cans would fare better than glass canning jars.

So, leave a little room for expansion in the jars?

I wouldn't take freezing into account but just leave the proper headspace. Freezing jars almost always results in cracked jars.

Also note that some canners and or pressure canners state specifically they should not be used on open flame burners, so that is something to watch for as well. I have 23 quart that should not be used on open flame and I use that on our glass top stove. The smaller one I use on our turkey fryer.

Bryce