I've kept a can of spam in my rig in the past when it was well below freezing, and it was just fine.

I don't reckon that meat expands like regular water when it freezes. I believe the water is bound up enough that even if you go below the freeze point, it will not work the same in a semi-solid suspension like this.

Spam has a lot of saturated fat and sodium, even the low sodium version.

Anyone ever try and dry it, like chipped beef?