Modeling the supercritical carbon dioxide inactivation of Staphylococcus aureus, Escherichia coli and Bacillus subtilis in human body fluids clinical waste

Human body fluids clinical waste poses a challenge to healthcare facilities because of the presence of infectious pathogenic microorganisms, leading concern for an effective sterilization method to eliminate the infectious threat for safe handling and disposal. In the present study, the supercritical carbon dioxide (SC-CO2) was utilized to sterilize human blood waste with varying pressure and temperature for a treatment time of 5-90 min. Modified Gompertz equation was employed to elucidate Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis-vegetative cell) inactivation curve in SC-CO2 sterilized human blood waste. It was observed that the experimental data was well fitted with the predicted value obtained from modified Gompertz equation. The SC-CO2 sterilization efficiency was compared with the steam autoclave treatment based on bacterial regrowth potential and scanning electron microscope image analyzes. The absence of bacterial regrowth and physicochemical destruction of bacterial cells revealed that SC-CO2 is an efficient sterilization technology to treat human blood waste. Thus, SC-CO2 sterilization method could be utilized to sterilize human blood waste in a healthcare facility to improve hospital hygiene by eliminating infectious exposure of human body fluids clinical waste, and to conduct safe handling and management of human body fluids clinical waste. (C) 2016 Elsevier B.V. All rights reserved.