Freeze-drying is the process of freezing and dehydrating fresh meat, fruits and vegetables in a vacuum.  The whole freeze-drying technology takes place at low temperatures, and the water in the frozen food does not melt into water, but sublimates directly out of the food into gas. The freeze-drying technology of pet freeze-drying food is basically the same, but frozen cat treats usually use pure natural meat, livers, fish and shrimp, fruits and vegetables as raw materials, without any additives such as attractant, preservative, oil and salt, which is an ideal natural pet food.