Sterilization is an important part of laboratory sciences. In many laboratories, containers and other labware must be sterile for research to be accurate. There are several types of sterilization: autoclaving, gas, dry heat, chemical disinfectant and irradiation. This a quick overview of each form of sterilization available:
Autoclaving : Autoclaving is generally steam sterilization for equipment and objects 121°C, 15 psi. All items should be washed beforehand, to prevent baking contaminents onto labware. Always be sure that caps are loosened or removed to prevent accidental implosion when autoclaving. Times vary for effective autoclaving.
Gas : Ethylene oxide is a popular way to sterilize medical implements, and kills bacteria, mold and fungi. However, gas sterilization should be used only for items which cannot withstand steam sterilization. Ethylene oxide is generally used to sterilize items that are heat or moisture sensitive.
Dry Heat : A non-corrosive way to sterilize which destroys by oxidation. However, it is less effective than moist heat and requires longer times and/or higher temperatures. It is mainly for use on materials that are damaged by or are impenetrable to moist heat.
Chemical Disinfectant : Several chemicals can act as disinfectants. For example, benzalkonium chloride solutions are rapidly acting biocidal agents with a moderately long duration of action and are active against bacteria and some viruses, fungi, and protozoa. Formaldehyde is a strong disinfectant and anti-bacterial agent, but it is nearly ineffective as a fungicide, insecticide, or larvacide. Other chemical disinfectants exist, but each is effective at different rates and for disinfecting different things.
Irradiation : Gamma Irradiation sterilizes or decontaminates by killing bacteria by breaking down bacterial DNA and inhibiting bacterial division by exposure to gamma rays. Gamma irradiation is not dependant on temperature or humidity, but on source strength and exposure time. Sterilization of some medical items is performed using gamma irradiation. Radiation passes through packaging, killing germs such as bacteria. The contents remain sterile until the packaging is opened.
NOTE: It is always recommended that you check with laboratory regulation prior to performing a sterilization.
Thursday 28 May, 2015