Disclosed is a sterilizing composition including (i) orthophthalaldehyde (ii) at least one glycol or polyol or derivative thereof (iii) a non-ionic first surfactant and (iv) a second surfactant having a cloud point in the range of about 30°C to 50°C. A process for preparing the compositions of the invention is also disclosed. The compositions of the invention are low or substantially non-foaming under high pressure, high temperature conditions, thus allowing maximum benefit from the new, more reliable, generation of automated endoscope reprocessing machines.
