Why must food be freeze dried in space?

Food must be freeze-dried in space to ensure it remains lightweight and shelf-stable, which is crucial given the limited storage space and weight restrictions on spacecraft. Freeze-drying removes moisture, preventing spoilage and reducing the risk of microbial growth, which is essential for long-duration missions. Additionally, this preservation method helps retain the food's nutritional value and flavor, making it more palatable for astronauts during their missions.