The microbial controls of antiseptics and disinfectants by membrane filtration: experimental evaluation of the interferences.

Microbiological investigations made by membrane filtration method on antiseptics and disinfectants demonstrated that the filtering membranes present very frequently a remarkable antimicrobial activity, even after washing with 300 ml of peptone water according to the guidelines of the Pharmacopoeia. The observed phenomena (appearance of inhibition zones, disappearance or decrease of the number of colonies forming units, release of antimicrobial properties to the cultural broths) can seriously diminish the validity of microbiological controls of antiseptics and disinfectants.