Considering quality isn't mentioned in the post, I am guessing that all spoilable items have no quality maybe? With whatever non-spoilable item they create being be the ones that roll for quality- It will be fine in that case don't worry.
I do hope they change the names of both systems though, like maybe 'decay' and 'purity', especially if they want to reuse these systems in the future (plus for mod creators too)