mikah wrote:If anyone could help I would appreciate it- my agar plates looks cloudy. I can see tiny particles suspended
I am using
2g vegemite
1g bonox
5g NaCl
5g peptone
15g agar
as per previous lab tech recipe
mix on magnetic stirrer on heat then pressure cook for 15min in conical flask
Q- am I meant to let it boil until it looks clear or does it stay cloudy?
I'm clueless.....
Experiment with the recipe until you get it right for you. Depending on climate you may need more than 15g of agar to get it to set (here in Central Queensland in summer I use 25g; expensive but it just won't gel otherwise).
Start with 800mL (for a final solution of 1000mL) of water. Begin to heat and add the agar while stirring. Be thorough.
The solution should be cloudy yellow at this point. Continue stirring and bring it to near boiling until it starts to go clear. It should turn somewhat translucent. When you can see a stirring rod held in the middle of the beaker, that's the sign your agar has properly dispersed through the solution and will gel when cool. (If you don't stir, the precipitate near the bottom will burn.)
Add salt, then peptone, and the extracts in turn. When they are mixed in, dilute to target volume, and place in conical flasks with cotton plugs to autoclave for 15 minutes. Then let cool to around 60 C and pour. (Or store in the fridge until needed.)
