Question

The large holes in ‘Swiss-Cheese’ are made by a

• A. Fungus that releases a lot of gases during metabolic activities
• B. Machine
• C. Bacterium that produces methane gas
• D. Bacterium producing a large amount of CO₂

Answer 1

The Correct Option is D

The characteristic "eyes" or holes in Swiss cheese are formed due to the activity of specific bacteria known as propionibacteria. These bacteria play a crucial role in the cheese-making process by consuming the lactic acid produced by other bacteria during fermentation. As a byproduct of their metabolic activities, propionibacteria release carbon dioxide (CO2) gas. This CO2 gas becomes trapped within the cheese, resulting in the formation of the distinctive holes or bubbles.

Thus, it is the presence of propionibacteria in Swiss cheese that leads to the production of a significant amount of CO2 gas, which in turn creates the large holes observed in the cheese.

Answer 2

The characteristic "eyes," or holes, found in Swiss cheese are a direct result of the metabolic activity of specific bacteria known as propionibacteria. These microorganisms are essential to the unique texture and appearance of this type of cheese.

During the cheese-making process, other bacteria first ferment the milk, producing lactic acid. Propionibacteria then consume this lactic acid. As a key byproduct of this consumption, the propionibacteria release carbon dioxide (CO₂) gas. 

This CO₂ gas, produced during the metabolism of lactic acid, becomes trapped within the semi-solid cheese matrix. Unable to escape, the gas accumulates, creating localized pockets that ultimately manifest as the distinctive "eyes" or bubbles that are hallmark of Swiss cheese.

In summary, the activity of propionibacteria is the *direct cause* of the formation of the characteristic holes. Without these bacteria consuming lactic acid and releasing CO₂, Swiss cheese would not have its signature appearance. It is the presence and metabolic activity of propionibacteria that are ultimately responsible for the large holes observed.