Complex sentence: The ancient Chinese found that salt, because it inhibits bacteria, was useful both in preserving foods and in controlling fermentation; without salt, the yeasts and sugars produced by vegetable decay rot and turn to alcohol.
Split into simpler sentences: The ancient Chinese found that salt, because it inhibits bacteria, was useful both in preserving foods and in controlling fermentation. Without salt, the yeasts and sugars produced by vegetable decay would rot and turn to alcohol.