since we no longer have those old-time canning contacts (I think this was mentioned in a pickle thread here too) ... the sauerkraut we like is sold at small specialty stores, incl butcher shops - it's from the heartland of Cdn sauerkraut - St Jacobs ON
Here is what the label says (i happen to have some in my freezer (yes - freezer))
St. Jacobs Foods
New Hamburg ON
"made naturally for you"
it says it contains cabbage and salt (that's it)
and is packaged in a clear plastic vacuum sealed bag
no additives or preservatives
i know this doesn't help the OP --- but for anyone who goes up to the sunshine coast (sechelt) - i have seen it at Butcher Dave's place (aka Butcher's Block meat market) on your right as you enter the big 4-way stoplight intersection in Sechelt - there is a coffee bistro place and dry cleaner and Lighthouse Cold Beer / Wine next to it. I think Dave is from that part of ontario, so i would think he knows what he's talking about re: this type of product.
i have even frozen it! and it when thawed, it was just fine.
a pkg is about $3.50.
i quickly googled and i found this ---
St Jacob's Foods
3171 Bleams E
New Hamburg, Ontario N3A 3J3