Final answer:
A 99.999% or 5-log reduction in microbial population typically indicates sterilization, which aims to completely eliminate all microbial life. This level of control is necessary in settings where the absolute absence of microbes is critical, such as in medical and certain food industry applications. Option A is the correct answer.
Step-by-step explanation:
Understanding 99.999% (5 log reduction)
When considering a method to control microbial growth, such as achieving a 99.999% or 5-log reduction in microbial population, one must determine the objective of the process. If the intent is sterilization, then the goal is to completely eliminate all forms of microbial life, including bacteria, viruses, and even hardy spores. To achieve this, one requires the use of extreme measures like autoclaving, which employs pressurized steam, or chemical sterilants capable of killing all microbes.
Pasteurization, on the other hand, is a gentler method that applies lesser amounts of heat and is designed not to sterilize, but to control microbial growth to levels safe for consumption while preserving food quality. It's effective at killing pathogens and reducing the number of microbes that cause spoilage but does not achieve complete sterilization.
In contrast, sanitization refers to reducing microbial numbers to levels considered safe according to public health standards. Methods can include hot water and chemical disinfectants. Unlike sterilization and pasteurization, sanitization does not necessarily kill all microbes but reduces them significantly.
Cleaning is the most basic level of microbial control, involving physical removal of dirt and organic matter, and may not necessarily kill microbes, although it often reduces their numbers.
With regard to the specifics of the question regarding 99.999% reduction, such efficacy is typically associated with sterilization processes where ensuring the absence of microbial life is critical. Using this percentage and log reduction, the correct answer option for achieving such a high level of microbial control is:
a. Sterilization.