ABSTRACT
INTRODUCTION A sterile medical product is one that is free of viable microorganisms. Most medical products produced under standard manufacturing conditions according to the FDA requirements (21 CFR 820 and 21 CFR Part 210/211) (1) have microorganisms on them, even though the numbers may be low. Such medical products are nonsterile. The purpose of sterilization then is to inactivate the microbiological contaminants and thereby transform the nonsterile medical products into sterile one. Also, the sterilization treatment must not render the medical product materials or functions unacceptable. Basic to the comprehension of a sterilization process is an understanding that the kinetics of inactivation of a pure culture of microorganisms by physical and/or chemical can be expressed by an exponential relationship between the numbers of microorganisms surviving and the extent of treatment with the sterilant. This means that there is always a finite probability that a microorganism may survive regardless of the extent of treatment. Therefore, for a given treatment, the probability of survival is determined by the number and resistance of microorganisms on or in the product and by the conditions used during the sterilization treatment. It follows that the sterility of any one medical product in a population subjected to sterilization processing cannot be guaranteed and the sterility of a processed population is defined in terms of the probability of there being a viable microorganism present on a medical product.
