Before commencing an investigation of the efficacy of the disinfectant a method of neutralising the disinfectant
at the end of the exposure period shall be demonstrated and documented. This shall include demonstration
that, for any neutralising agent used, neither the neutralising agent nor its reaction product with the
disinfectant are microbicidal. When a secondary host such as a cell culture is used as the detection system for
the survival of test organisms the absence of carry over effects on the cell culture system and detection of low
numbers of test organisms added as a challenge to the test system shall be demonstrated.