Food has been preserved for later use since the ancient times. The food has to go through preservation process, which helps in slowing down the spoilage, so that it can be stored for a longer period of time. The aim of the preservation process is to prevent the growth of bacteria, yeast, fungi, etc. It also aims to prevent visual deterioration of the food. There are different methods, which can be used for preserving food, like drying, refrigeration, freezing, vacuum packing, pickling, or using modified atmosphere. Using dry ice is the most common form of modified method of preserving food.
Preserving food using dry ice has become popular for various reasons. When dry ice is used, the atmosphere around the food product is modified. The oxygen level concentration around the food product is reduced as the carbon dioxide concentration increases. This method helps in preventing insects as well as mold and oxidation from destroying the food. It is said if grains are stored using this method, they may be edible for as long as five years. The freezing happens at -109° Fahrenheit, which ensures there is no mushy texture on frozen items.
How to Preserve Food Using Dry Ice
One can make the most of dry ice in summers to preserve food, when there is temporary or long term power outage, since it is a common feature in summers.
How to Use Dry Ice in Freezers
A small quantity of dry ice should be placed on the top shelf of the freezer, so that the frozen foods will remain unspoiled for about four days. Dry ice should be kept in the lowest shelf of refrigerator to preserve the food. When ice is placed in the refrigerator or freezer, care should be taken that you do not allow pressure to build up.
How to Use Dry Ice for Flash Freezing
Place a thin layer, about 3 inches in thickness, of dry ice at the bottom of the container. Cover the dry ice with brown paper or heavy foil. Place the food product to be stored in freezing pans lined with wax paper. Then the pans can be placed in the container. Close the lid of the container, but make sure that the lid of the container is not sealed. Over a period of time, dry ice will change states from solid to gas and cause gas pressure, which can prove to be harmful. Therefore, the container should not be sealed. Let the food item remain in the container for about half and hour. By this time the food product will be frozen. Then remove the food item from the container and place it in storage bags ensuring all air is removed from the bag. Seal the bag and place the bag in the freezer or in another dry ice container.
Tips on Using Dry Ice for Preserving Food
While using dry ice for preserving food, it is important that dry ice is not handled with bare hands, as it can cause serious burning. The dry ice containers or coolers should not be sealed or clamped for the gas build up can prove to be dangerous. When using dry ice, it is best to be in a room, that is well ventilated, lest the gas released by the dry ice can cause suffocation or breathing problems. When dry ice is placed on food products, it should be covered either in a newspaper or towel. You will have to ensure that bottles or cans are not in direct contact with dry ice. There are chances that the bottles or cans will freeze and rupture, as the ingredients inside may expand. Last but the most important is to keep dry ice out of reach of children.
Although it is one of the most commonly used methods of preserving food, it should be done with utmost care. Also it is important to note that the nutrient value of the food product will diminish over a period of time, therefore, it is best to resort to fresh food as far as possible.