In the context of microbial control, the microbial death rate is typically:

• A. variable and unpredictable over time
• B. constant over time
• C. non-linear over time

Answer: (B)

Verified step by step guidance

1. Understand that the microbial death rate refers to the rate at which microorganisms die when exposed to a lethal agent, such as heat, disinfectants, or radiation.
2. Recall that in microbial control, the death of microorganisms often follows first-order kinetics, meaning the rate of death is proportional to the number of living cells present at any given time.
3. Recognize that because of this proportionality, the microbial death rate remains constant over time when expressed as a percentage or fraction of the population dying per unit time.
4. Express this concept mathematically using the equation for first-order kinetics: \(\frac{dN}{dt} = -kN\), where \(N\) is the number of viable cells, \(t\) is time, and \(k\) is the death rate constant.
5. Conclude that since \(k\) is constant, the microbial death rate is constant over time, leading to a logarithmic decline in the number of viable microorganisms.