What is Freeze Dried Food and how is freeze dried food made?
Freeze-dried food is a type of food preservation method in which water is removed from food through a process called sublimation, which is the transition of a substance from a solid to a gas without passing through a liquid state. This process preserves the food by removing the water, which is a breeding ground for bacteria and other microorganisms.
The process of making freeze-dried food typically involves several steps:
- Harvest or purchase fresh food.
- Clean and prepare the food for drying by removing any dirt or debris and cutting it into small pieces if necessary.
- Blanch the food to kill bacteria and inactivate enzymes that can cause spoilage.
- Quick-freeze the food by placing it in a freezer at extremely low temperatures, typically -40°F (-40°C) or colder.
- Place the frozen food in a vacuum chamber and reduce the pressure to below the triple point of water, which is the temperature and pressure at which water can exist in all three states (solid, liquid, and gas).
- Sublimate the frozen water in the food, which causes it to transition directly from a solid to a gas, leaving behind only the dried food.
- Seal the dried food in airtight packaging to protect it from moisture and oxygen, which can cause spoilage.
- The food is ready to be eaten or stored for a long time.
This process preserves the food for a long time and the food can be rehydrated to be consumed.
How long can freeze dried food last? Do different foods last longer from others?
Freeze-dried food can last for many years if it is stored properly in airtight packaging and kept in a cool, dry place. The shelf life of freeze-dried food can vary depending on the type of food and how it was processed. In general, freeze-dried fruits and vegetables can last for up to 25 years, while freeze-dried meat, poultry, and seafood can last for up to 30 years. Dairy products, such as cheese and powdered milk, can last for up to 20 years.
The shelf life of freeze-dried food is also affected by factors such as temperature, humidity, and exposure to light and oxygen. High temperatures and humidity can cause the food to spoil more quickly, while low temperatures and low humidity can help to preserve the food for a longer period of time.
It’s important to note that, while freeze-dried food can last for a long time, it’s still best to consume it within the recommended time frame. The nutritional quality of freeze-dried food may decrease over time, especially if the food is exposed to heat, light, or oxygen.
It’s also important to check the packaging for the best before date and inspect the package before consuming the food to ensure that it’s still in good condition. Any signs of discoloration, off-odors, or other signs of spoilage should be considered as an indication that the food should not be consumed.
