3. Why does food need to be dried?
Drying inhibits the growth of bacteria, yeasts, and mold through the removal of water. The purpose of drying is to retain the physico-chemical properties of materials, to ensure, in many cases, the preservation of materials over prolonged periods, and to eliminate excess weight in shipping.

In freezing, water in food turns into ice and hence, makes the water unavailable for reactions to occur and for microorganisms to grow.  It is suggested that before freezing the fresh vegetables, must be blanched first to stop the enzymatic activity (that can cause alterations in their nutritional values).

 For blanching, vegetables dropped into a pot of boiling water. Allow them for 1-2 minutes and then immediately stop the cooking process by removing them from the boiling water and dropping them into ice water. When cooled they are ready to put into freezer bags, pressing as much air out of the bag as possible and then into freezer. 

As freezing one of the most commonly used processes commercially and domestically for preserving a very wide range of food including prepared food stuffs that would not have required freezing in their unprepared state, such as potato waffles are stored in the freezer, but potatoes themselves need only a cool dark place to ensure several days storage. 

At commercial level, cold stores provide large-volume, long-term storage for strategic food stocks held in case of national or international emergency in many countries. In general, freezing does not destroy spoilage or contamination microorganisms but it stops their growth as long as the food is kept at -180C. Any microorganism present will become active as the food thaws. Properly Proper packaging of food in freezer paper or freezer containers can prevents any deterioration in its quality and damage occurs once food comes in contact with the dry air of a freezer.

2. How does fermentation help in preserving food products?

The fermentation process involves the oxidation of carbohydrates to generate a range of products, which are principally organic acids, alcohol, and carbon dioxide. Such products have a preservative effect by limiting the growth of spoilage or pathogenic microbiota in the food.

3. What is your opinion on the safety of fermented food?

In my opinion, fermented foods generally have a good safety record, but improperly fermented foods may be unsafe. The fermentation of vegetables is primarily due to the lactic acid bacteria, although yeasts and other microorganisms may be involved, depending on the salt concentration and other factors.