Test: Microbes in Household Products - NEET MCQ

Saccharomyces cerevisiae is also known as baker’s yeast. This yeast is used for fermenting wheat flour after it is kneaded. Similarly, the dough which is used for making bread is also fermented using baker’s yeast.

The dough which is used for making foods such as dosa and idli is fermented by using bacteria like Streptococcus. The puffed-up appearance of this dough is due to the production of CO₂ gas.

• Propionibacterium sharmanii is responsible for the production of large holes in Swiss cheese. This is a process that occurs during the cheese's aging process.
• Propionibacterium sharmanii is a type of bacteria that can convert lactic acid into propionic acid, carbon dioxide, and water. This bacterium is specifically used in the production of Swiss cheese.
• During the cheese-making process, the cheese is warmed, which encourages the growth of Propionibacterium sharmanii. As the bacteria metabolize the lactic acid, they produce carbon dioxide gas.
• The carbon dioxide gas cannot escape the cheese, which is semisolid, leading to the formation of bubbles or holes within the cheese.
• As the cheese ages, the bacteria continue to produce gas, and the holes, or 'eyes', in the cheese continue to grow larger. The size of the holes can be controlled by adjusting the temperature and aging time of the cheese.

• Both statements 1 and 2 are correct. A small amount of curd added to the fresh milk as inoculum or starter contains millions of lab, which at suitable temperatures multiply, thus converting milk to curd.
• It improves its nutritional quality by increasing vitamin B₁₂. In our stomach too, the lab plays a very beneficial role in checking disease-causing microbes.

Rennet is extracted from the stomach of the calf and is used to prepare cottage cheese.

LAB stands for Lactic acid bacteria. Indian curd is prepared from both skimmed and cream milk by inoculating the milk with lactic acid bacteria.

Large holes in Swiss cheese are formed by the CO2 produced (causing holes) by a bacterium called Propionibacterium shermanii.

In the preparation of idli batter, the batter is fermented using bacteria or yeast. During fermentation, CO₂ bubbles which are released get trapped in the gluten, thus making idli soft and puffy.

The dough used for making bread is fermented by saccharomyces cerevisiae or commonly called baker’s yeast. Co2 released during the process of fermentation gives a puffy appearance to the dough. It is used to make foods like idli, dosa, bread, etc.

• Both a and r are true and r is the correct explanation of a the dough used for making bread is fermented by saccharomyces cerevisiae or commonly called baker’s yeast.
• CO₂ released during the process of fermentation gives a puffy appearance to a dough. It is used to make foods like idli, dosa, bread, etc.

Roquefort cheese is formed by ripening with the fungi penicillium roqueforti, for a particular flavour.

Pasteurisation is a process that is undertaken to kill all pathogenic microbes. Methods of pasteurisation of milk used commercially include a low-temperature holding (lth) method and a high-temperature short-time (test) method. The first process employs equipment capable of exposing milk to a temperature.

The large holes in 'Swiss cheese' are due to the production of a large amount of CO₂ gas by a bacterium named Propionibacterium sharmanii.

In 1864, Pasteur discovered the process of pasteurisation. It is a process of preservation of milk, wine and other liquids by heating for a short period and then cooling suddenly. This kills most of the microbes.

Live microbial food is called as probiotics, therefore single-cell protein is also referred to as probiotics. It is protein-rich microbial biomass which can be used as food and feed.