Technical Guidelines for Cryopreservation and Lyophilization of Pathogenic Microorganism Strains

Pathogenic microorganisms, defined as microbial entities capable of invading the host and causing infection or communicable disease, encompass a taxonomically diverse assemblage that includes viruses, bacteria, fungi, and rickettsiae.Cryopreservation is a technique that stores microbial cultures in a low-temperature environment, reducing their metabolism to the minimum or even to a complete standstill so that the organisms enter a semi-dormant or fully dormant state. Lyophilization (freeze-drying) is a preservation technique in which microorganisms are first frozen in a cryoprotective medium. Water is then removed by sublimation under vacuum and reduced pressure. Since the process avoids abrupt changes, cellular damage is minimized, and microbes are kept in a dry, oxygen-free state where their physiological activities are markedly inhibited.Standardized, scientifically sound low-temperature and freeze-drying preservation techniques for pathogenic microorganism strains are essential for ensuring their long-term, stable, and high-quality storage. This chapter outlines the procedures for low-temperature and freeze-drying preservation of microorganism strains, providing technical guidance for institutions engaged in the storage, preservation, utilization, and production of pathogenic microorganisms.