Certified Professional Food Safety (CP-FS) Practice Exam

Which type of bacteria do not need oxygen to survive?

1. Aerobic bacteria

2. Facultative bacteria

3. Obligate anaerobic bacteria

4. Optional aerobic bacteria

The correct answer is: Obligate anaerobic bacteria

Obligate anaerobic bacteria are the correct choice because they thrive in environments devoid of oxygen. These bacteria utilize fermentation or anaerobic respiration processes to generate energy, which means they not only tolerate but actually require a lack of oxygen to survive. Their metabolic processes are specifically adapted to avoid the toxic effects of oxygen, which can be harmful or lethal to them. In contrast, aerobic bacteria require oxygen for their growth and metabolic functions. Facultative bacteria are versatile, as they can grow in both the presence and absence of oxygen, switching metabolic processes accordingly. The term "optional aerobic bacteria" is not a recognized classification in microbiology, making it an incorrect choice in this context. Understanding these distinctions is crucial in food safety, especially regarding contamination and spoilage, as different types of bacteria behave differently under varying environmental conditions.