Be careful not to talk, sing, or whistle while performing sterile procedures.Use only sterile glassware and other equipment.If you remove a cap or cover, and have to put it down on the work surface, place the cap with opening facing down.Return the cover as soon as you are finished. until the instant you are ready to use it and never leave it open to the environment. Never uncover a sterile flask, bottle, Petri dish, etc.Always cap the bottles and flasks after use and seal multi-well plates with tape or place them in resalable bags to prevent microorganisms and airborne contaminants from gaining entry.Do not unwrap sterile pipettes until they are to be used. Use sterile glass or disposable plastic pipettes and a pipettor to work with liquids, and use each pipette only once to avoid cross contamination.Avoid pouring media and reagents directly from bottles or flasks.Wipe the outside of the containers, flasks, plates, and dishes with 70% ethanol before placing them in the cell culture hood.
If gloves are not used, it is necessary to wash hands before and after testing. This will prevent any foreign contaminants from coming in contact with the customers and sample during testing. Always wipe your hands and work area with 70% ethanol.This could be either by the technical team preparing for and clearing up after a piece of practical work (for example, in the case of glassware to be used), or by the worker during the course of the practical (for example, in flaming a wire loop). All items which come into contact with microorganisms must be sterilised before and after each such exposure.The parts of sterile pipettes which will be put into cultures or sterile vessels must not be touched or allowed to come into contact with other non-sterile surfaces, such as clothing, the surface of the working area, or the outside of bottles/ test tubes.During manipulations involving a Petri dish, limit exposure of the sterile inner surfaces to contamination from the air.On opening a test tube or bottle, the neck must be immediately warmed by flaming (see below) with the vessel held as near to horizontal as possible and so that any movement of air is outwards from the vessel.While vessels are open, all work must be done close to a Bunsen burner flame where air currents are drawn upwards.Vessels must be open for the minimum amount of time possible.Complete all operations as quickly as possible, but without any hurry.Start the operations only when all apparatus and materials are within immediate reach.If the bench surface is difficult to clean, cover the bench with a sheet of tough material which is more easily disinfected. Ethanol disinfection is recommended because of its rapid action. Make transfers over a disinfected surface.
FOUR PRINCIPLES OF ASEPSIS WINDOWS
limiting the duration that cultures or media are uncapped and exposed to the air.Cleaning and disinfecting lab surfaces prior to use.The aseptic techniques control the opportunities for contamination of cultures by microorganisms from the environment, or contamination of the environment by the microorganisms being handled.However, there are a number of simple, common sense procedures that will reduce the risk of culture contaminations.One should always remember that a completely sterile working environment does not exist.Since the goal of a biologist is to grow microorganisms or eukaryotic cells without the introduction of extraneous organisms, aseptic techniques are crucial for accurate and meaningful experimentation.While such actions are sometimes called “sterile technique,” that terminology is appropriate only in reference to preventing the introduction of any organisms to the laboratory or medical equipment and reagents (e.g., during surgery).Aseptic technique is a set of routine measures that are taken to prevent cultures, sterile media stocks, and other solutions from being contaminated by unwanted microorganisms (i.e., sepsis).
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