Q1.
“But why is oil added to the pickle?”, Disha asked eagerly.
Answer
Paati's answer: “Oil stops air from getting in. That keeps the pickles safe!” The oil floats on top and makes a cover that air cannot pass through.
Here is how a pickle is protected, in order:
- The raw mango pieces are first rubbed with salt. Salt pulls the water out of them.
- Spices are added. Many spices, like black pepper and mustard, make it hard for microbes to grow.
- Mustard oil is poured on top until the pieces are fully covered.
- Oil does not mix with water, and it is heavy enough to stay as a layer above the pickle.
- With no air below the oil, microbes cannot grow — so the pickle stays good for months.
Finding #4: Oil keeps out air and stops the growth of microbes.
Salt takes away moisture
Oil takes away air
Together = a pickle that lasts for months
Oil takes away air
Together = a pickle that lasts for months
Why air matters so much: Microbes are living things. Most of the ones that spoil food need air to grow, just as we do. Cut off their air, and they simply cannot get going — even though the food itself has not been changed at all.
Two pickle rules every home follows: always use a clean, completely dry spoon, and keep the oil layer above the pieces. A wet spoon brings water and microbes in, and a piece sticking out above the oil is the first one to grow mould.