The control of microbial growth is necessary in many practical situations, and significant advances in agriculture, medicine, and food science have been made through study of this area of microbiology.
"Control of growth", as used here, means to prevent growth of microorganisms. This control is effected in two basic ways:
By killing microorganisms or
By inhibiting the growth of microorganisms.
Control of growth usually involves the use of physical or chemical agents which either kill or prevent the growth of microorganisms. Agents which kill cells are called cidal agents; agents which inhibit the growth of cells (without killing them) are referred to as static agents. Thus the term bactericidal refers to killing bacteria and bacteriostatic refers to inhibiting the growth of bacterial cells. A bactericide kills bacteria, a fungicide kills fungi, and so on.