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Food preservation techniques are ways to stop or greatly slow down spoilage while keeping flavor, texture and nutritional value as much as possible.
If you don't preserve your food somehow, it will start to spoil soon after it is harvested. The most common ways to preserve food that will keep food safe are canning, freezing and drying.
Other methods that both help preserve food (and also add flavor) include pickling, salting, preserving in syrup or alcohol, and sugar crystalization.
Canning
When thinking about preserving food, most people think of canning. Canning is done by preparing foods, sealing them in sterile cans or jars, and boiling the containers to kill or weaken any remaining bacteria and create a vacuum seal. The two main types of canners are boiling water canners and pressure canners. Each method is best used with particular foods. Pickling and the creation of jams, preserves, and jellies also use canning techniques.
Drying
One of the oldest and most reliable methods for preserving food is drying. Since ancient times people have dried foods to store them for later use.
Drying reduces water activity and delays or prevents bacterial growth. Many fruits can be dried; drying is often used to preserve apples, bananas, mangos, papaya, pears, and others. Currants, raisins and sultanas are all types of dried grapes, for example. Drying is also the usual method for preserving cereal grains. Tomatoes are also commonly dried.
Freezing
Another very old method to preserve food is freezing. Many Arctic communities preserved food in holes dug into the ice. Scandinavians preserved fish (especially herrings) this way. Freezing provides long-term storage for strategic food stocks held in case of national emergency in many countries. Some foods, including many raw vegetables, do not freeze well.
This newsletter is not big enough to provide specific information on preserving specific foods - we can only provide an overview of possible techniques. However, there is a lot of online information on the subject. We would recommend checking out the National Center for Home Food Preservation which has specific information on canning (click here), drying (click here) and freezing (click here), as well as other methods such as pickling, fermenting and making jams and jellies (see the menu to the left at any of the previous links).
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