Microbiological control is a regulatory requirement and one that can be defined as the continued interaction of science and applied technology with products, processes, materials, equipment, and personnel entering the manufacturing areas. In the ISO 14644-1, control of microbial contamination is addressed. A good microbiological control program starts with understanding the risks for microbial contamination in the manufacturing process and identification of possible types of contaminants. The results obtained from such risk assessment can be used in the design of facilities and equipment as well as when establishing protocols regarding equipment and personnel. Once possible sources of contamination have been identified, control and preventative measures can be implemented and qualified/validated.