Drying meat out over smoke will help to preserve it, as the CO and other emissions and heat will kill off bacteria and slow the growth of new colonies. It's pretty easy to discover by accident- meat that's been overcooked on a wood fire will last longer than meat than meat that isn't.

Other cultures did things like ferment meats and salt cure them, but if you're inland away from easy access to excess salt, it's pretty hard to do that and not get food poisoning.