Core tip: High-level decontamination processes to ensure iatrogenic infection prevention in the delivery of high-quality gastrointestinal (GI) endoscopy services are essential. There are three important steps that must be highlighted: manual washing, automated endoscope washer reprocessing and adequate drying/storage after rinsing. Our experimental data demonstrated that surveillance culture monitoring that can detect unsuccessful decontamination provides a much greater assurance of quality control for high level disinfection. This monitoring should be taken into account in order to ensure safety when a patient receives GI endoscope service. Randomized surveillance culture monitoring of the reprocessing process in each month is important for quality control and in ensuring patients’ safety.