Question

Salt is applied on the inner surface of pickle jars and the pickle is covered with oil. Why is this done?

Answer 1

Salt and oil are used to prevent the oxidation of the pickle which leads to rancidity and spoiling of the food.

Answer 2

Answer:

Salt is applied on the "inner surface of pickle jars" and the pickle is being covered with oil. This is done to prevent microbial growth in the pickle that derive its nutrition from the pickle and thus destroy it, turning the pickle bad. The presence of salt causes increased solute concentration, that causes the "microbes to lose water" by plasmolysis and thus kills the microbes. The oil, beside adding taste to the pickle, helps to keep the microbes at bay, by preventing direct contact with the pickle and the air, as these microbes are generally air borne.