Question

Latika observed her grandmother adding lots of salt on unripe mangoes to prepare pickles. Her grandmother also added an excess of oil in the pickle jar. What could be the reason for it?

• A. Salt prevents the growth of microorganisms by retaining moisture in the food item and oil provides an environment in which microorganisms cannot grow.
• B. Salt prevents the growth of microorganisms by forcing them to lose water by osmosis and oil provides an environment in which microorganisms cannot grow.
• C. Salt prevents the growth of microorganisms by retaining moisture in the food item and oil prevents their growth by forcing out water from them by osmosis.
• D. Salt prevents the growth of microorganisms by forcing them to lose water by osmosis and oil prevents their growth by retaining moisture in the food item.

Answer 1

The correct option is B Salt prevents the growth of microorganisms by forcing them to lose water by osmosis and oil provides an environment in which microorganisms cannot grow.

Osmosis is also used for preserving fruits and meats, though the process is quite different for the two. In the case of fruit, osmosis is used to dehydrate it, whereas, in the preservation of meat, osmosis draws salt into it, thus preventing the intrusion of bacteria.
Microbes cannot grow in a condition where oil is present. It is because it makes a shield on top of the pickle which prevents aerobic conditions inside the jar. Thus, the correct answer is option B.