A process useful for disinfecting medical instruments is presented involving reacting a hydrogen peroxide donor with an N-acyl compound in an aqueous medium having a pH of 9 to 11 to form an acylated hydrogen peroxide preparation, reducing the pH of the acylated hydrogen peroxide preparation to pH 7 to 9； and contacting the acylated hydrogen peroxide preparation with a medical instrument. The process provides good antimicrobial activity with little corrosion. The process is effective against mycobacteria.
