aseptic techniques

• what is meant by aseptic techniques


  this is a technique that includes the apparatus and equipment are kept free of micro-organisms
• what are the two main purposes of aseptic techniques


  preventing contamination of pure culture by microbes from the environment and preventing contamination of the environment by cultures being grown
• in what ways do you prevent the surrounding environment from contaminating the pure culture


  sterilise all the equipment ,handle cultures carefully,disinfect the work benches
• what should be used to disinfect the worktops


  3% lysol
• how do you prevent the surrounding environment from being contaminated from the cultures being grown

  sterilise the work surface before and after the experiment , lift lid of agar dish to 45 degrees , seal dish with adhesive tape
• what is the first step when inoculating an agar dish


  pass the metal loop though the flame until its red hot , allow to cool
• when inoculating an agar dish what do you do after the loop is sterilised


  hold the bottle containing the bacterial culture in one had and remove the lid with the other
• when inoculating an agar dish what should you do after the bacterial culture has been opened


  flame the neck of the culture bottle for 2-3 seconds
• when inoculating an agar dish what should you do after you've famed the lid


  open the petri dish to 45 degrees and allow the entry of the inoculating loop
• when inoculating an agar dish what should you do after you've inserted the inoculating loop


  secure the dish with adhesive tape , but not all the way
• why should the petri dish not be secured to tight


  it could cause anaerobic conditions and potential lead to growth of pathogenic organisms
• when inoculating an agar dish what should you do when the petri dish is secured with adhesive tape


  incubate at 25-30 degrees for 24-48 hours
• why would you not incubate bacteria at 37 degrees


  to discourage the growth of any mammalian pathogenic bacteria
• what are optimum conditions for mammalian pathogens


  37 and obligate anaerobes
• when inoculating an agar dish what is the final step


  sterilise all the equipment after use
• in a laboratory what is the preferred method of sterilisation


  an autoclave
• what is an autoclave


  this is a sealed vessel in which glass and metal is sterilised
• describe how an autoclave works


  the equipment is heated to 121 degrees in steam under high pressure in an autoclave bag for 15 minuets
• how hot is it in an autoclave


  121 degrees
• how long does it take for an autoclave to sterilise equipment


  15 minuets
• what are the two ways in which equipment can be sterilised

  an autoclave or gamma irradiation
• how are plastic equipment such as petri dishes sterilised

  gamma irradiation
• what is the preferred disposals of plastic equipment once its been used


  a bio hazard waste bin
• if there is no bio-hazard waste bin how ill plastic equipment be disposed of


  sealed in an autoclave bio hazard bag , autoclaved at 121 degrees for 15 minuets and discarded safely in a bin
• what are the two main ways to culture bacteria in a lab


  on a nutrient agar plate or in a conical flash with a nutrient broth
• how do you prevent the contamination of a culture


  flame the inoculating loop,have a Bunsen flame on a work surface to produce a convection current and only lift the lid of the agar plate to 45 degrees
• where does a ectoparasite live


  they live on the outside of a host
• where do endoparasites live


  inside a host