Testing standards for sporicides

Sporicidal products are of considerable importance in healthcare environments due to the requirement for products that are capable of dealing with contamination with Clostridium difficile spores. Sporicidal testing standards to validate the claims of sporicidal activity are an important tool in the evaluation of commercial sporicides. Within Europe there are a number of sporicidal testing standards which are often used to validate the claims of commercial sporicides. However, the extent to which these standards reflect the practical application of sporicides in healthcare settings is limited since they employ long contact times (≥30 min) and do not involve surface contamination. Alternative international standards are available which employ contaminated carriers rather than spore suspensions, and the Organisation for Economic Co-operation and Development is currently developing a unified set of standards which are more realistic in their design than the currently available European standards. This paper reviews the currently available testing standards for sporicides, highlighting the key procedural differences between them and the extent to which they reflect the practical application of sporicidal products. Some of the common problems and errors associated with the application of the European sporicidal standard methods are also highlighted and discussed. Finally gaps in the currently available testing standards are identified and discussed.