Which one of the following is not fermented by microbes to make foods?

The correct answer is Option (3) → Rock salt

Fermentation is the breakdown of organic food matter by microbes such as bacteria and yeast. It changes the taste and texture of the food, as in curd, idli dough and bread.

Option (1) Fish — Fermented by microbes to make foods. Fish is rich in protein and other organic matter, so microbes can grow on it. Fermented fish is a traditional food in many places.

Option (2) Soyabean — Fermented by microbes to make foods. Soyabean is a protein-rich seed. Microbes ferment it into foods such as soya sauce.

Option (3) Rock salt — Not fermented by microbes to make foods. Rock salt is a mineral, sodium chloride, dug out of the earth. It is not organic matter, so microbes have nothing in it to break down.

Option (4) Bamboo shoots — Fermented by microbes to make foods. Bamboo shoots are young, soft plant parts. They are fermented by microbes into traditional foods, especially in north-east India.

NCERT Extract:
Microbes in Household Products – …