Dear Ziva, The more porous or uneven the surface the more difficult antimicrobial effectiveness becomes. However, normally it is not our lab studies that show this deficiency as it is exactly that, a lab study and not application in the clean room. It is normally in our "in situ" (field) studies or in daily operations where we notice possible differences as application and dry time of the disinfecting agent on the surface may vary from area to area. The field studies bring together antimicrobial effectiveness and our cleaning SOP's. If we pass antimicrobial effectiveness and fail the field studies, we need to revisit our cleaning SOP's as they may be lacking in their content. Sincerely, Art Vellutato, Jr. Veltek Associates, Inc. [log in to unmask] At 11:44 AM 4/26/2000 -0700, you wrote: >>>> ArialWhat kind of recoveries are seen in sporeformers and vegetative organisms while using coupon method for disinfectant qualification.What kind of recovery difference is seen between smooth surfaces as stainless steel and glass vs floor and wall material. Any input will be greatly appreciated. ArialZiva Abraham <<<<<<<< ------------------ The PMFList (http://microbiol.org/PMFList_info.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community.