What does the term "viable cells" refer to in microbiology?

The term "viable cells" in microbiology specifically refers to cells that are capable of reproduction when cultured. This means that these cells have the ability to grow and proliferate under suitable environmental conditions, which is a key aspect of assessing microbial populations.

Viability is often determined through various methods, such as culturing on agar plates or using selective media that allow only live cells to grow, thereby providing a clear indication of cell health and potential for growth. Viable cells are essential in research and industrial applications, as they can be used for fermentation processes, the production of antibiotics, and the study of microbial ecology.

In contrast, other choices do not align with the definition of "viable cells." Being visible under a microscope does not inherently indicate viability, as dead cells can also be observed. Non-viable cells are, by definition, those that cannot survive or reproduce, contradicting the concept of viability. Lastly, while some viable cells may cause disease, not all viable cells are pathogenic, making that option too narrow and not representative of the overall definition.