What is the use of keeping food in airtight containers?

Answer 1

Products (food) kept in this manner are normally those whose dryness has to be maintained. These will be powders such as flour, cake, biscuits(cookies) coffee, tea etc.

These products can and do absorb moisture in the air. As most of these items groups are used in cooking or and stored in an environment where cooking take places the moisture levels are exceptionally high. Therefore they become soft in the case of biscults and cake lines and those of a powder become sticky.

In an airtight container this reduces the moisture contact opportunities.

Answer 2

Keeping food in air tight containers helps to slow down the oxidation process