To desiccate means to preserve food by removing moisture from it — or, more generally, to dry something out completely. As a preservation method it is among the oldest known: removing water drops the water activity below the point where bacteria, yeasts, and moulds can grow, so desiccated coconut, dried milk, dried herbs, and fruit leathers keep for months without refrigeration. Industrial desiccation runs from hot-air drying to freeze-drying, each trading cost against quality. The word also describes the unwanted version of the same process — salad leaves desiccating in a dry refrigerator, bread staling as moisture migrates away. Whether deliberate or accidental, desiccation is the same physics: water leaving a material for drier surroundings. Food packaging’s moisture barriers exist largely to control which direction that journey takes.