Aseptic broth transfer and colony selection
What is it about?
Aseptic broth transfer and colony selection is all about performing basic bacteriological transfer techniques using broth and agar cultures. This will also determine how well one handles bacteriological cultures aseptically.
Procedures:
- To start off, we have samples of Escherichia coli in nutrient broth, Micrococcus luteus on an agar slant, and Escherichia coli on a nutrient agar streak plate.
- Firstly, we would use an inoculating loop to transfer E.coli from the broth culture into another test tube of fresh nutrient broth.
- Next, we would use the inoculating loop to take a sample of M.luteus from the agar slant and transfer it into a test tube of fresh nutrient broth.
- Then, we would use the inoculating loop to transfer a sample of E.coli from the nutrient broth and streak it onto a test tube of fresh agar slant.
- Lastly, we would use the inoculating loop to take a sample of E.coli from the nutrient agar streak plate, and transfer into a test tube of fresh nutrient broth. (the inoculating loop is flame sterilized after each transfer)
Results:
E.coli from nutrient broth into nutrient broth
Broth turns turbid
Sediment is seen
M.luteus from agar slant to nutrient broth
Broth turns creamy yellow
Sediment is seen
E.coli from nutrient broth to agar slant
Pellicle is seen at the top of the tube
E.coli from nutrient agar streak plate into nutrient broth
Broth turns cloudy
Sediment is seen
However if any step has been carelessly done, it’ll result in… CONTAMINATION!
