Pasteur's Experiment.
Pasteur's Experiment.
Dear All - I am having trouble with the peptone broth that did NOT become contaminated with microorganisms as expected during Pasteur's experiment. Must admit the peptone I am using has been in the lab for 25 years (That's how long I've been here) God knows how many years before that!! So maybe it's too old!! Just like I am feeling!!!! I used the usual recipe i.e. 5 teaspoons of peptone dissolved in 100ml of hot water and then diluted to 1 litre. from the Clearway Science Teacher's Resource Book. then 50ml into a conical flask- one open and one fitted with a coiled tube and boiled gently for 5 minutes. Is this the recipe most of you use?? If not, would you mind telling me what recipe you do use, your assistance would be greatly appreciated. Cheers Judy.
Pasteur's Experiment
Hi Judy,
Have a look at HSC Online, i.e. http://hsc.csu.edu.au/biology/core/bett ... 43net.html.
This suggests using meat extract cubes. You can buy these from a supermarket considerably fresher than the peptone you have. Our peptone is a similar vintage to yours. It predates me and I have been here a similar time to you - 27 years.
When making up protein solutions for food tests I always used peptone but after a short time it stank! I changed to using granulated gelatin as the protein source and it works well and is much more pleasant to the nose.
Robbie
Have a look at HSC Online, i.e. http://hsc.csu.edu.au/biology/core/bett ... 43net.html.
This suggests using meat extract cubes. You can buy these from a supermarket considerably fresher than the peptone you have. Our peptone is a similar vintage to yours. It predates me and I have been here a similar time to you - 27 years.
When making up protein solutions for food tests I always used peptone but after a short time it stank! I changed to using granulated gelatin as the protein source and it works well and is much more pleasant to the nose.
Robbie
Pasteur's Experiment.
Dear Robbie - Thank you very much for your help re the peptone broth
and also the protein solutions, I too have the same problem - so I will be changing to the gelatin solution as suggested. Once again thanks a lot!! Cheers Judy.
and also the protein solutions, I too have the same problem - so I will be changing to the gelatin solution as suggested. Once again thanks a lot!! Cheers Judy.
