A composition or concentrate for cleaning medical or dental instruments comprising in combination a protease and a biostatically effective phenoxy alcohol such as phenoxyethanol selected such that at a working solution dilution of the combination, the phenoxy alcohol is at a concentration below the MIC of the selected phenoxy alcohol against Pseudomonas aeruginosa (ATCC 15442), and wherein the combination is nevertheless effective to reduce a 6 log concentration of Pseudomonas aeruginosa (ATCC 15442) by at least a 1 log concentration within 4 hours. The composition or concentrate may further include or more hydrolases and or boron or a boron compound. The composition may be used in methods for cleaning a soiled medical or dental instrument, for example in an ultrasonic bath.
