What is the primary mechanism of preservation achieved by the ancient technique of drying?

Removing moisture so microorganisms cannot multiply

Drying is recognized as one of the oldest and most fundamental methods utilized for food preservation, whether through natural solar drying or artificial heat sources like dehydrators. The effectiveness of this technique rests entirely on controlling the water activity within the food item. Microorganisms, including yeasts, molds, and bacteria, require a certain amount of available water to metabolize, grow, and reproduce. By systematically removing this moisture content—a process that fundamentally alters the food's structure—the environment becomes inhospitable for microbial life. This lack of available water effectively stops multiplication, thereby preserving the food over extended periods, particularly when applied to high-acid foods like fruits.