Question

- Proper aseptic technique is crucial to ensuring growth of pure bacterial colonies. What is one experimental way you can test your practices to confirm that you are using proper aseptic technique? (5 points)

- In a laboratory setting, what are three ways you can properly sterilize culturing equipment? (5 points)

- For each inoculation tool, give one scenario in which use of that tool would be appropriate. (5 points)

- Do some research and describe two or three scenarios in which it would be preferable to use a stab tube vs. a growth plate. (Hint: What do bacteria use to help them move? Can motility be used to help identify many medically important pathogenic bacteria such as the Enterobacteriaceae?)

Answer 1

Leave a petri plate poured with media at the work place, open the lid, and leave it for some time. Then incubate the petri plate for 24 hours. If bacteria colonies appear on the plate, then the aseptic techniques you are following are not proper.

Cultural equipment is properly sterilized by Autoclaving, dry heat sterilization, and filter sterilization (used for heat labile components).

Inoculation loop is used to pic single colony and to spread on the medium to get isolated colonies.

Micropipette is used to inoculate liquid culture of bacteria for the serial dilution, and to inoculate them on liquid culture.

Forceps is used to inoculate fungal or plant tissues.

Stab tube method is used to lessen the contamination possibility. This method is also useful for identifying the motile bacteria. Bacterial inoculum punctured in one place is mobilized leaving with mark behind and can be easily observed.