Aseptic Techniques & Cell Counting Essay Example | Topics and Well Written Essays - 2500 words

Aseptic Techniques & Cell Counting - Essay Example flame loops, put slides in jars of Lysol or Chloros, put pipettes in their proper receptacles, and discard cultures into their appropriate autoclave buckets. Several different methods are used for sterilization and some of which we will use today. The maintenance of sterility requires the use of Aseptic Technique. The object of this is to prevent any form of contact between the sterile growth medium (e.g. petri dish containing nutrient agar) or the pure culture and any source of contaminating organisms. The new student should be aware that it is very easy to sterilize a pipette or bacteriological loop and then to place it on the non-sterile bench whilst picking up something else. Sources of contamination include: Any non-sterile surface, liquids, or air. Air is a very important contamination source because of; free-floating fungal or bacterial spores, liquid droplets, dust particles, dried skin scales, all of which may contain bacteria and/or fungi. Good aseptic technique is crucial for work in microbiology, microbial genetics, or biotechnology. Flaming using a Bunsen Burner is the classic method for rapid sterilization of bacteriological loops, glass pipette and bottle or flask necks. Flaming needs to be done for several seconds, long enough to raise the temperature well above 100 oC. Bottle necks should be rotated in the flame for 5 sec. or so to achieve this. For all basic techniques in microbiology and for today’s exercise in liquid transfer and inoculation, manual dexterity in removing screw-on lids is important. The most reliable technique is to use the little finger to unscrew and hold lids and plugs, leaving the other fingers free to hold loops or pipettes etc. The operator (i.e. you!) is the most likely source of small particles floating in the air and landing on your work. Breathing, coughing, sneezing and talking may all lead to some production of air-borne particles (aerosols) but more importantly respiratory secretions and saliva