Freeze dried food is cooked or fresh foods that have been frozen then had the water removed. This creates a light weight, tasty, preserved food that can be quickly prepared.
The freeze-dried food process varies from one food to another, but following is a general process:
Test and Preparation
The food is first checked for purity. Fruits and meats are tested for bacterial counts. The type of preparation will be dependent on what products are currently being dried;
Some foods must be cooked before they are freeze dried. These types of foods are cut into small pieces and then put in large industrial kettles to cook, and then they are freeze dried;
Fruits and vegetables are purchased in a ready to use state, with the exception of peas and corn, which are quickly scalded, a process called blanching.
Freezing the Freeze Dried Food
The food is spread out on large metal trays that can be stacked up to 30 trays high on a cart;
The cart is wheeled to a room where the temperatures are extremely cold; causing flash freezing of the food.
Drying Chambers For the Freeze-Dried Food
After freezing, the carts are moved to the vacuum drying chambers. It is a long horizontal cylinder that is relatively long and holds the trays snugly in place, with semi elliptical ends that are hinged;
Once the food has been placed in the tube, it is closed and sealed. Most companies have at least 20 active drying chambers at any given time. The drying includes sublimation, which is when a solid food is forced to change to a gaseous material without becoming liquid;
Freeze Dried Food Ready For Market
After the drying process is complete, the freeze dried food is ready to be distributed to wholesalers who will bring them to market.