Which of the following methods is considered a -cidal control method?

The method identified as a -cidal control method is radiation. This term refers to processes that kill microorganisms, rather than simply inhibiting their growth. Radiation, particularly ionizing radiation (such as gamma rays and X-rays), has high energy that damages the DNA of microbial cells, leading to cell death. This makes it effective for sterilizing equipment and preserving food by eliminating bacteria, viruses, and parasites.

While filtration and temperature control can both be used to control microbial growth, they do not necessarily kill all microorganisms. Filtration removes microbes from liquids or air but does not kill them, while temperature control can either inhibit growth or kill organisms depending on the temperatures and duration applied—e.g., pasteurization effectively reduces pathogens but may not eliminate all microorganisms.

Moist heat, especially at high temperatures (like boiling or autoclaving), is also a -cidal method, as it effectively kills microorganisms through denaturation of proteins and other cellular components. However, in the context of the question, radiation stands out as a widely recognized method specifically associated with reliable microbial cell death across various applications.