Essay On Sterilization

Disinfection is the removal of many, but not all microorganisms (Weebly). This removal of organisms creates less of a chance of infection occurring. While some spores or organisms survive disinfection, there are methods of sterilization that can be used to kill them completely. Sterilization involves the complete removal or killing of all microorganisms, even spores which are highly resistant (Weebly). Sterilization methods can act in physical or chemical manners, so many different approaches are used to achieve sterilization (Weebly). The most effective physical methods usually involve heat, this can ensue with moist or dry heat. Moist heat sterilization is done at the boiling point of water and will not result in killed spores, but instead

Autoclaving is the most popular form of moist heat sterilization because it combines heat and pressure to result in thorough killing of spores, which is hard to achieve. For this method the bacteria is cooked under a pressure of 15 psi and temperature of 121°C for 15 minutes, because of the pressure this higher boiling point then 100°C can be met and results in the dead spores (Rhinehart). The dry heat version of sterilization is done at 160-170 °C. A great example of dry heat sterilization is the flaming of a tube to prevent contamination of cultures. The tube is passed through a flame quickly without it getting to hot and then can be used. In addition, incineration is a dry heat method that is demonstrated when using the inoculating hoop to transfer a colony of bacteria (Rhinehart). The hoop is first left in the Bunsen burner flame until it glows red; it is now sterile and can be used when cooled. Along with the science related sterilization methods there are also methods that relate to our day to day lives. Pasteurization is the manner used to heat milk to a desired temperature followed by cooling that kills any pathogenic bacteria in the milk (Madigan et