Nutrient Agar

[Nikki]

Thanks for the additional tips. As soon as I get a chance this term to practise I will have a go at some of these ideas

Nikki

[JudyM]

I usually make up a bulk lot of N.A. in a large beaker & once dissolved I then transfer it to test tubes.Sometimes the biology students pour there own plates but I mostly use boiling tubes which holds enough agar for 2 plates. Just fill to the white mark & then cover with foil. I then pressure cook them & any left over tubes get marked with the date & kept in the fridge.
This means I have a ready supply that only needs to be remelted.(Need to use pressure cooker for this).I've kept agar this way for over a year without it deteriorating.

Cheers[/img]

[Robbie]

Thanks to all for the suggestions. I still use a pressure cooker but we do have a microwave available which I will use next time.

I also have left the prepared plates in the frig for many months without any ill effect.

After the experiment is over, how long do you leave the plates in the microwave to destroy all the wee beasties?

Regards,
Robbie

[DJ]

Hi Robbie,

I know you asked about disposal of agar plates using a microwave. I can't answer that, but you mentioned you have a pressure cooker.

Using that, seal agar plates in an oven bag (yes, oven bag). Put them in the pressure cooker with about 2 - 3 cm water. I was taught to sterilise them for 45minutes.

Regards,
DJ

[Mojo]

Heating method is the best . Autoclave method while getting the mixture sterile is not air tight due to expansion and lid left loose, so what ever was supposed to glue my Agar boiled out and I was left with non setting Agar . Heating method even though not sterile, agar plates do not develope pathogens otherwise mouldy bread would be dangerous . And as a bonus if something small pops up it can end up being interesting as yogurt wasn't that exiting.

[Robbie]

One (small) way of keeping the cost down is by using gelatine instead of peptone. Gelatine is readily available from the supermarket and does not start to stink from being too old as peptone does. Also I have found peptone can become a solid lump. Gelatine is a good replacement as the protein ingredient.

Hope this helps.

Robbie