The drying method is the oldest method for food preservation. This method dates back to as early as 12,000 BC, where the sun and wind would naturally dry the foods. Over time new ways have been discovered to help improve the drying method. People built "still houses" for the purpose of drying foods. Using a fire not only dries the food but it will also give it the smoky flavor. Then ovens and dehydrators came around.
The freezing method was the next to come into light for an effective way to preserve foods. Cellars, caves and streams within cold geographic areas were put to good use during this time. People would set the food outside in below freezing temperatures to freeze it and then store it in less than freezing areas. The "quick freeze" process really sprouted this method and helped it improve.
The pickling method was originated when food was place in "old" beer or wine, which has low pH levels and get turned into vinegars. In the 16th century, the pickling process started to be more discovered and more experimented. People would start adding spices to see if it gave it flavor, and it was a trial and error to figure out how long everything would last in this solution.
The canning method was introduced in the 1800's in means to keep food for the military. This method is to keep food from spoiling by putting them in jars and sealing them with heat.
The salting method, although it is not known exactly when it started it is thought to be at at least 2000 BC.
