Hani Ali BTEC National diploma in science
Practical report
Microbial techniques
Introduction
I will do three different practical experiments to investigate the growth and isolation of bacteria and the characteristics of different microbes.
They are:
- Pouring
- Streaking
- Environment
Pouring plates
Pouring plates can be used to investigate if bacteria can grow on a solidified nutrient agar by following the aseptic techniques carefully.
The aseptic techniques used were:
- Flaming the neck of the bottle by passing the opening through a Bunsen burner
- The lid of the bottle is opened using the small finger of the other hand during procedure to avoid placing the lid on the bench, where it can be contaminated
Apparatus
Bunsen burner
Bottle containing a nutrient agar
Petridish
Matches
Method
- Remove the bottle containing molten nutrient agar from the hot water. Allow the liquid agar to cool down.
- light the Bunsen burner and adjust it to blue flame
- Open the bottle with little finger on the other hand to avoid placing the lid on the bench.
- Flame the neck of the bottle for a few seconds. This is done to produce an upward flow of air from the bottle so that any organism in the area will not fall into the bottle.
- Pour the molten agar slowly into the base of sterile petridish, lifting the lid only as much as necessary. Do no not spill agar on the edges of dish.
- Replace the lid and allow the agar to set, by gently rotating to get even layer of agar.
- Secure the dish with adhesive, by using two pieces of tape to fasten the lid, but do not seal all the way round as this cold create anaerobic condition and encourage the growth of possible pathogenic microorganisms.
- The plate can be used for streaking or spreading, when the agar solidifies.