Well you know the standard "no heat" reply is that you will have to
worry about wild yeast if you do not pasturize. You could sulfite,
which would work.

You still have the school of thought that non-pasturized apple juice
(like unpasturized honey) makes a better drink. If you do decide to
use it unpasturized, pitch a healthy yeast starter. I would say 1/2
cup slurry/5 gallons.

There is a good article in thei month Wine maker about spontaneous
fermentation though. It is just as pertinent to cider fermentation as
it is to wine fermentation.