Microbes in Household Products Questions in English

(B) Indian curd is produced by the fermentation of milk. The process involves adding a small amount of curd (starter or inoculum) to warm milk. This inoculum contains lactic acid bacteria $(LAB)$,primarily $Lactobacillus$ species such as $Lactobacillus$ $acidophilus$. These bacteria multiply and convert the lactose sugar present in milk into lactic acid,which coagulates the milk proteins (casein) to form curd.

(A) The large holes in 'Swiss cheese' are caused by the production of a large amount of $CO_2$ by the bacterium $Propionibacterium$ $sharmanii$.
During the fermentation process, this bacterium releases carbon dioxide gas, which gets trapped in the cheese curd, creating the characteristic large holes.

(C) The puffed-up appearance of dough used for making foods such as dosa and idli is due to the production of $CO_2$ gas.
This process occurs during fermentation,where microorganisms like bacteria (e.g.,Leuconostoc and Streptococcus species) break down carbohydrates present in the dough.
As a byproduct of this anaerobic respiration,$CO_2$ is released,which gets trapped in the dough,causing it to rise and appear puffed up.

(A) The traditional drink known as 'toddy' is a fermented beverage produced from the sap of various species of palm trees,such as the Palmyra palm ($Borassus$ $flabellifer$). The sap is collected by tapping the inflorescence of the palm,which then undergoes natural fermentation by yeasts and bacteria present in the environment to produce the alcoholic drink.

(B) Lactic acid bacteria $(LAB)$,such as $Lactobacillus$,are responsible for converting milk into curd. These bacteria grow in milk and produce acids that coagulate and partially digest the milk proteins,thereby converting it into curd.

(C) The correct answer is $C$.
Roquefort cheese is ripened by growing a specific fungus,$Penicillium \ roqueforti$,on it.
This fungus provides the cheese with its characteristic flavor and texture.

(A) $LAB$ (Lactic Acid Bacteria) converts milk into curd.
This process improves the nutritional quality of curd by increasing the content of Vitamin $B_{12}$.

(A) The correct answer is $A$.
Large holes in Swiss cheese are formed due to the production of a large amount of $CO_2$ by the bacterium $Propionibacterium$ $shermanii$ during the fermentation process.

(C) - Swiss cheese.
$Swiss$ cheese is produced by the fermentation of lactic acid by the bacterium $Propionibacterium$ $shermanii$,which produces propionic acid,acetic acid,and carbon dioxide.
The acids provide flavor to the cheese,and the carbon dioxide,which becomes trapped in the curd,produces the characteristic holes in the cheese.
In contrast,$Penicillin$ is obtained from the fungus $Penicillium$ $notatum$,$Statins$ are produced by the yeast $Monascus$ $purpureus$,and $Cyclosporin-A$ is produced by the fungus $Trichoderma$ $polysporum$.

(B) Carbon dioxide.
The dough becomes puffy due to the presence of $CO_2$ gas liberated by bacteria during the process of fermentation.
In this metabolic process,bacteria break down carbohydrates into ethanol and $CO_2$ gas,which gets trapped in the dough,causing it to rise.