Read the following statements about microbes in household products:
A. During growth in milk, lactic acid bacteria produce acids that coagulate and partially digest the milk proteins.
B. The LAB in the curd added to fresh milk as a starter multiply and convert milk to curd, which lowers its nutritional quality.
C. The dough used for making foods such as dosa and idli is fermented by bacteria.
D. The dough used for making bread is fermented using baker’s yeast (Saccharomyces cerevisiae).
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A, C and D only
A. During growth in milk, lactic acid bacteria produce acids that coagulate and partially digest the milk proteins. — True. Lactic acid bacteria (LAB) such as Lactobacillus grow in milk and make acids. The acids coagulate and partly digest the milk proteins, which sets the curd.
B. The LAB in the curd added to fresh milk as a starter multiply and convert milk to curd, which lowers its nutritional quality. — False. Turning milk into curd improves its nutritional quality, by increasing vitamin B12. The statement says the opposite.
C. The dough used for making foods such as dosa and idli is fermented by bacteria. — True. The book states that this dough is fermented by bacteria; the CO2 released gives it the puffed-up look.
D. The dough used for making bread is fermented using baker’s yeast (Saccharomyces cerevisiae). — True. Bread dough is fermented by baker’s yeast.
NCERT Extract:
Microbes in Household Products – “… Micro-organisms such as Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it to curd. During growth, the LAB produce acids that coagulate and partially digest the milk proteins. A small amount of curd added to the fresh milk as inoculum or starter contain millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality by increasing vitamin B12. In our stomach too, the LAB play very beneficial role in checking disease-causing microbes. The dough, which is used for making foods such as dosa and idli is also fermented by bacteria. The puffed-up appearance of dough is due to the production of CO2 gas. … Similarly the dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae).”