Concepts Microbial growth is defined as an increase in cellular constituents and may result in an increase in a microorganism's size,population number,or both. A wide variety of techniques can be used to study microbial growth by following changes in the total cell number,the population of viable microorganisms,or the cell mass. Solid objects can be sterilized by physical agents such as heat and radiation;Liquids and gases are sterilized by heat,radiation,and filtration through the proper filter. A knowledge of methods used for microbial control is essential for personal and public safetyConcepts • Microbial growth is defined as an increase in cellular constituents and may result in an increase in a microorganism’s size, population number, or both. • A wide variety of techniques can be used to study microbial growth by following changes in the total cell number, the population of viable microorganisms, or the cell mass. • Solid objects can be sterilized by physical agents such as heat and radiation; Liquids and gases are sterilized by heat, radiation, and filtration through the proper filter. • A knowledge of methods used for microbial control is essential for personal and public safety