Final answer:
The correct answer is c. lower temperatures require longer times to be effective. Higher temperatures kill microbes more quickly, so less time is needed when using higher temperatures to control microbial growth.
Step-by-step explanation:
Among the options given regarding the relationship between time and temperature in the control of microbes, the correct answer is c. lower temperatures require longer times to be effective. High temperatures kill microbes more quickly, so higher temperatures require shorter periods of time to be effective. Therefore, the inverse is true: lower temperatures are less effective and thus require longer exposure times to achieve the same level of microbial control. This principle is used in methods such as refrigeration, where lower temperatures slow down microbial metabolism and growth, thereby helping to preserve food or medical supplies.In methods such as heat sterilization, the thermal death time (TDT) is the length of time needed to kill all microorganisms in a sample at a given temperature, demonstrating that a higher temperature achieves this more rapidly. This is further supported by the concept of the D-value, which is the time required for a one order-of-magnitude decrease in the number of organisms, or the death of 90% of the population.Lastly, certain factors can compromise the effectiveness of a disinfecting agent, such as the presence of organic material or biofilms on surfaces, which can increase the time needed for the disinfecting protocol to work effectively.