Final answer:
Freeze-drying removes water from food in a vacuum to prevent spoilage and preserve original qualities for long-term storage at room temperature.
Step-by-step explanation:
Freeze-drying is a method of preservation that rapidly freezes the food and then removes water by sublimation in a vacuum, preventing microbial growth and hence spoilage without altering the food's original texture, flavor, and smell, enabling long-term room temperature storage.