There is a selected portion of the normal growth curve which is referred to as the logarithmic growth phase or the log phase. When cells begin to grow, we usually observe a period of no apparent growth which we refer to as the lag phase. This occurs because cells are making necessary adjustments to adapt. Next we experience the rapid growth or the log phase previously described. As cell mass becomes large, nutrients are exhausted and metabolic byproducts collect.
Growth tapers off and the population remains constant for a time.
This is referred to as the stationary phase of growth. With no intervention in the system the population will enter a death phase and total numbers of organisms will decline. Enumeration of Cells Numbers of microorganisms can be estimated based on cell counts, cell mass, or activity. A direct count of cells may be made by examination of a known volume of cell suspension under a microscope. This method is rapid and requires minimal equipment.