Bacterial Role in Fermentation Processes

Steps:

• Identify products involving microbial fermentation: alcohol, bread, yogurt, and penicillin.
• Recall that bacteria perform lactic acid fermentation in dairy products.
• Distinguish bacterial processes from those using yeast or fungi.
• Match yogurt production to bacterial involvement via milk acidification.

Why C is correct:

• Yogurt is made by bacteria like Lactobacillus bulgaricus and Streptococcus thermophilus fermenting lactose in milk into lactic acid, thickening it per the lactic acid fermentation process.

Why the others are wrong:

• A: Alcohol is produced by yeast (Saccharomyces) fermenting sugars into ethanol, not bacteria.
• B: Bread rises due to yeast producing carbon dioxide, with no primary bacterial role.
• D: Penicillin is an antibiotic derived from the fungus Penicillium, not bacteria.

Final answer: C