Question

Yogurt is produced by the fermentation of milk using:

• A. Saccharomyces cerevisiae
• B. Acetobacter aceti
• C. Lactobacillus bulgaricus (with Streptococcus thermophilus)
• D. Penicillium roqueforti

Hint:

Remember: Yogurt = Milk + Friendly bacteria (L. bulgaricus + S. thermophilus). It's a classic fermentation duo in dairy products.

Answer 1

The Correct Option is C

Yogurt is made through the bacterial fermentation of milk, a process that converts lactose (milk sugar) into lactic acid.
This process is carried out by a specific combination of bacteria, primarily Lactobacillus bulgaricus and Streptococcus thermophilus.
These bacteria work symbiotically:
- Lactobacillus bulgaricus produces acids and peptides that stimulate Streptococcus thermophilus.
- Streptococcus thermophilus rapidly lowers the pH, creating a suitable environment for Lactobacillus bulgaricus to thrive.
Let’s evaluate the incorrect options:
- Saccharomyces cerevisiae is a yeast used in baking and alcohol production.
- Acetobacter aceti is used in vinegar production by converting ethanol to acetic acid.
- Penicillium roqueforti is used in cheese ripening, especially blue cheese, not in yogurt.
Thus, the correct microbial culture for yogurt production is the combination of Lactobacillus bulgaricus and Streptococcus thermophilus.