Swiss cheese is ripened by

Options

A. Propionicabacterium shermanii
B. Penicillium roqueforti
C. Penicillium camemberti
D. Streptococcus lacits

Answer

To determine which bacterium is responsible for ripening Swiss cheese, we can analyze each of the provided options step by step.

### Step 1: Understand the Role of Bacteria in Cheese Ripening
Cheese ripening involves specific bacteria that contribute to the flavor, texture, and appearance of the cheese. Different types of cheese are ripened by different bacteria.

**Hint:** Consider the characteristics of Swiss cheese and what makes it unique.

### Step 2: Evaluate the First Option - Propionibacterium shermanii
Propionibacterium shermanii is known for its role in Swiss cheese production. This bacterium ferments lactic acid and produces carbon dioxide gas, which forms the characteristic holes (or "eyes") in Swiss cheese.

**Hint:** Focus on the specific features of Swiss cheese, like the presence of holes.

### Step 3: Evaluate the Second Option - Penicillium roqueforti
Penicillium roqueforti is a mold used in the production of blue cheeses, such as Roquefort. It is responsible for the blue coloration and flavor but is not involved in Swiss cheese ripening.

**Hint:** Think about the types of cheese that use molds versus those that use bacteria.

### Step 4: Evaluate the Third Option - Penicillium camemberti
Penicillium camemberti is used in the ripening of soft cheeses like Camembert and Brie. It contributes to the creamy texture and white rind but does not play a role in Swiss cheese.

**Hint:** Recall the specific cheeses associated with this mold.

### Step 5: Evaluate the Fourth Option - Streptococcus lactis
Streptococcus lactis is involved in the production of various dairy products, including some cheeses, but it is not specifically responsible for the unique characteristics of Swiss cheese.

**Hint:** Consider the primary bacteria that contribute to the distinct features of Swiss cheese.

### Conclusion
After evaluating all options, it is clear that **Propionibacterium shermanii** is the correct answer, as it is responsible for the ripening of Swiss cheese by producing carbon dioxide, which creates the characteristic holes in the cheese.

**Final Answer:** Swiss cheese is ripened by **Propionibacterium shermanii**.