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Can people please tell me what broth you use for the Pasteur experiment. In the last couple of years the teacher has used a beef cube dissolved in water, but to no success. Wasn't sure whether the stuff was too salty or what, but it hasn't worked as it should. Any successes would be greatly appreciated.
Cheers Dime

We use Peptone broth, 1teaspoon peptone/ 100mL water

I use the same Nutrient broth for Pasteur's Exp as I do for Agar plates, just without the agar powder
It goes something like this

5g peptone
5g NaCl
2g Vegimite
1g Bonox

all dissolved in 1 litre of water. (I use a hotplate and magnetic stirrer)

If it has boiled for 10 minutes, I assume it is sterile!

To make nutrient agar plates, I just add 15g of agar powder to this broth.

If I don't need a whole litre, I just halve the quantities.

Cheers
Ian

I've used Ian's recipe too and worked fine, teachers were happy. Thanks, Ian!

Thanks guys, you're champions

i've been asked for the same prac, teacher is happy for me to make it with stock cube.
I dont think i have any peptone- anything else?

Stock cubes and the liquid stock that you purchase from supermarkets all have ingredients to delay or prevent bacteria growing.
I just boil up a few chicken wings, or a drumstick.. the prep room always smeels nice on those days!

i use "preservative" free beef stock

I use a broth made from chicken wings or hearts from dissections. One teacher insists on vegemite and has very little success.

Following Year 10 projects in which tea grew mould in about 2 days one group has tried that!

I'll let you know how it went.

Its like growing mould on bread. The commercial bread has so much addiditives it just doesn't mould.

I use dog bones this year and boiled them up and then strained them. We haven't had any growth yet. Any idea how long should it take to get a result??

....but who donated their dog???

Ian

AS soon as I hit submit I knew someone would pick that up!!! Ha!!ha!!

I had trouble with using broth from supermarket, Too many preservatives so I just boil up some chicken wings, works beaut every time

The teacher and I decided to try both the peptone recipe and the chicken broth to see which is best. So currently smelling out the preproom with a drumstick cooking away. Thanks everyone for your input. Cheers

making my broth now with Ians recipe.

I found some peptone - but it is rock hard in the bottle, and it stinks!
So i have poured in some boiling water to soften it a bit and with the spatula have broken off some and poured the water into my broth...hope it works!

last year the prac didn't work, all that used was beef stock cube in hot water...hmmm out to do better this year! (i wans't herelast yr!)

woohoo my 'lets chuck things in and caall it broth' approach has worked - there is growth on what there should be, and no growth on what there shouldn't be - mission accomplished!

Thanks to the knowledgable chemtalkers! xx

Thats great Narelle. I had success with my mince(for one class) and dog (beef) bones (for the other class) too. Both classes had really good growth where the were supposed to and none where they weren't. That is the first year since I have worked here that it has been a success so I am celebrating.

and the other thing - i had about 400mls left over of the broth, so i added 100mls, agar and boiled - presto, agar plates for year 7 - all in the name of not wasting!

Hi Guys
We're doing the Pasteur experiment and every year I've used peptone. Ran out, order more and have got to work to find delivered Tryptone (Casein Trypsic Peptone). I don't even know what that is, any ideas what I would use that for.
Krysia

I think it is the same thing with a different name.