ABSTRACT
INTRODUCTION Moist heat sterilization in an autoclave is certainly the most widely utilized means of sterilization within the healthcare industry. It may also be the oldest method in use with the first practical sterilizer dating to the late 19th century (1). The vast industry experience with steam sterilization has resulted in the development of a variety of steam processes adapted for specific applications. In each of these, the sterilization process is accomplished by the presence of liquid water on the surface of the microorganism at elevated temperatures (2). The liquid water is necessary for coagulation of proteins within the microbe that result in its death and is implicit in “moist heat” sterilization.a In steam processes, the liquid water can be provided by saturated steam in contact with the surface (as utilized in hard goods sterilization) or via water content in a liquid filled container (as in media preparation or terminal sterilization of finished products). The requirement for liquid water must not be overlooked; sterilization with superheated steam (where no liquid is present) has far more in common with dry heat processes than it does with moist heat. A graph of the saturation curve for steam is shown in Figure 1.
