The time in minutes at a specified temperature required to kill a population of cells is termed: (Use standard thermal lethality terminology.)

Introduction:
Thermal processing metrics distinguish between partial and complete inactivation. This question focuses on the parameter describing complete kill at a fixed temperature: thermal death time (TDT).

Given Data / Assumptions:

• Population of cells is defined for the test condition.
• Temperature remains constant during the assay.
• We seek the time for total inactivation, not a log reduction.

Concept / Approach:
TDT is the minimum time required to kill a specified microbial population at a given temperature. It differs from D value (time for 90% reduction) and from TDP (lowest temperature that kills in 10 minutes). F value integrates lethal effect relative to a reference temperature (e.g., 121 °C in canning).

Step-by-Step Solution:
Interpret the prompt: “time in minutes at a specific temperature” to kill the population. Map definitions: total kill at fixed temperature → TDT. Differentiate from D value (one-log kill) and TDP (temperature for kill in 10 min). Select “thermal death time (TDT).”

Verification / Alternative check:
Thermal death curves relate survivor counts to time; complete inactivation time at fixed temperature corresponds to TDT.

Why Other Options Are Wrong:

• Decimal reduction time (D value): Time for 90% reduction, not complete kill.
• Thermal death point (TDP): Lowest temperature to kill in 10 minutes, not a time at fixed temperature.
• F value: Equivalent lethal time at a reference temperature across a process, not a single-point measure.

Common Pitfalls:
Confusing D value and TDT due to both using minutes at a temperature; the endpoint (90% vs 100%) differs.

Final Answer:
thermal death time (TDT) is the correct parameter.