Freeze dried foods are getting more and more popular. Freeze dried food is produced by freezing food products, removing moisture from it and sealing it in air tight container. These foods have a very long shelf life at normal temperatures. And they do not require much preparation or cooking to be consumed. Once prepared these foods taste a lot like the natural products.
This method of preservation was invented during the World War II and it was initially used for preserving blood without refrigerating it and damaging the plasma. Later on the same technology was applied to food products. One of the first products that came to customers in a freeze dried form was coffee. Today many food products are being freeze dried.
These foods have many advantages. They are very lightweight and do not require much space to be stored. That is why these foods are very popular among tourists and survivalists. These foods do not require refrigeration which makes storing and shipping a lot cheaper for suppliers. Due to these factors freeze dried foods are growing their popularity.
The main disadvantage of freeze dried food is the cost. These products are very expensive when compared to canned or frozen foods.
Freeze dried foods are produced on large plants with expensive modern equipment. Freeze drying process may vary in details from one manufacturer to another. Different times, temperatures, pressures could be used. We will describe some basic stages of the process below.
First of all food products are checked for purity. They are also tested for bacterial counts and spoilage. Some types of food must be cooked prior to freeze drying. For example, meats and seafood are cooked at the first stage. Fruits and vegetables are simply washed. Coffee comes to the plant as a concentrated liquid.
After preparation foods are spread on flat surface and are placed into cold rooms with temperature around minus 40 degrees C. As the temperature is extremely low the food is frozen quickly.
Afterwards the foods are taken into a vacuum drying chamber. When the food gets inside of it, the chamber is tightly closed and sealed. The drying process is also known as sublimation. Ice crystals that are present in frozen food pieces are changed into a gaseous state without becoming liquid water. This is accomplished by evacuating the air and creating the vacuum along with heating the food pieces with heat lamps. The time for this process varies from four to twelve hours and even more.
The dried pieces are removed from the chamber and once again tested for moisture content. Afterwards foods may be reduced to a powder or even blended together to meet customers’ needs.
To prevent absorbing moisture from the air freeze dried foods are packed in air tight containers.

This planet gets nasty – time to be prepared. Learn more about food storage – this information can save your life. Visit this food storage blog for useful updates in the food storage industry.