- A Penicillium roqueforti
- B Propionibacterium shermanii
- C Lactobacillus helveticus
- D Streptococcus thermophilus
Correct answer: B. Propionibacterium shermanii
Explanation: Propionibacterium shermanii produces large amounts of CO2 during cheese ripening, creating the characteristic holes (eyes) in Swiss cheese.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers