Decontamination with hydrogen peroxide: use and technical developments

ABSTRACT

This article compares the concepts of sterilization, disinfection and decontamination with reference to the different scopes thereof. Decontamination by hydrogen peroxide vapor and its use for conditioning the Sterility Test Isolators are discussed. A technologically new method for the vaporization ofthe hydrogen peroxide and its dosage control is presented.

Keywords: Sterilization, sterile, disinfection, chemical bio-decontamination, hydrogen peroxide, autoclave,
sterilizer, sterility test isolator, washers.

STERILIZATION, DISINFECTION, AND DECONTAMINATION: A TERMINOLOGICAL REVIEW

For a long time, the word sterilization has been used to indicate those processes, in food and pharma-industry or in hospital care, targeting the complete inactivation of viable microbial species on the surface and/or in the bulk of an object, including bacterial spores. According to a widely accepted definition, an object is sterile when completely free of contamination due to viable organisms. Therefore, sterility could be seen as an absolute concept: an object is sterile, or it is nonsterile. However, if we move from the rather abstract field of definitions to every day practice, things grow more complex: how can we objectively state that an object is sterile?

A common feature of all the known methods for testing sterility condition is the destruction of the sterility, if any, of the object being tested, thus making it no longer usable for its intended scope: in other words, no sterility test methods are known for a given object, that completely respect the integrity of it, without affecting its properties and damaging, more or less, the condition, if any, of sterility. In the case of packaged sterile products, it is even possible to say that no non-destructive sterility tests exist. This paradox can be expressed by saying that sterilization is a special process, where the results of processes (efficacy of sterilization) cannot be verified by subsequent inspection and testing of the product (the items sterilized) (Publimed, US National Library of Medicine, PMID: 10402868).

Therefore, a statistical verification of a successful sterilization is the sole economically sustainable alternative which implies the necessity of attaining a very high probability that a batch of the sterilized product does not contain non-sterile items. For these reasons, the industrial sterilization is defined as ‘a process used to render a product free of viable organisms with a specified probability’ (PDA, TR#1 revised 2007).