AndyAmine. Posted May 21, 2006 I have some questions about Agar I was hoping could be answered by some of our resident experts. How long can Agar (either on plates or in a jar) stay at room temps before being unusable? Is an Agar more likely to contaminate if left in the light? Is there any reason why agar plates cant be stored upside down, so that condensation/myc-piss drips downs rather than spreading on the plate I will have some more in the near future. Share this post Link to post Share on other sites
alkatrope Posted May 21, 2006 I have some questions about Agar I was hoping could be answered by some of our resident experts.How long can Agar (either on plates or in a jar) stay at room temps before being unusable? Is an Agar more likely to contaminate if left in the light? Is there any reason why agar plates cant be stored upside down, so that condensation/myc-piss drips downs rather than spreading on the plate I will have some more in the near future. We did some bacterial agar plates at school a month or two ago. They've been in a 37C oven for for that long and aren't cracking up. I'm pretty sure they last a while fresh. It's recommended to store them upside down, due to condensation. Sorry not sure about the light, but I'd assume they're better off out of direct sunlight. Share this post Link to post Share on other sites
occidentalis Posted May 21, 2006 How long can Agar (either on plates or in a jar) stay at room temps before being unusable? If it's not contaminated, the only decomposition that will be ocurring will be chemical - which means it will last a long time unless you put some fragile compounds in there. Unless it's years old (by which time it would become contaminated anyway) I'd be happy to use it. Is an Agar more likely to contaminate if left in the light? Dunno. I doubt it. Try it and see. Is there any reason why agar plates cant be stored upside down, so that condensation/myc-piss drips downs rather than spreading on the plate No, in fact this is commonly done and highly recommended. Share this post Link to post Share on other sites
Shroom-Aura Posted May 21, 2006 (edited) Im not resident expert but I did pass a course in Aseptic Technique (bacteria culturing on agar not at all disimilair to fungi culturing) as part of a TAFE certificate. It is very easy and simple. I have even done a few mushroom (cubes) plates at home always without a glovebox and without any contamination. Agar can lasts ages before becoming unusable. After about 6 months of fairly poor storage the agar in my cube cultures looked a bit ragged and probably unusable. It will not contaminate if left in the light, contamination can only get to the plate by physical means. And yes it is better to store the plates upside down, as you said the condensation that builds up on the top wont drip down on ur culture and possibly contaminate it if they are upside down. In the lab they seal plates with parrafilm to prevent contamination while still allowing gas exchange. I have used saran wrap with similar results. Edited May 21, 2006 by Trich-Aura Share this post Link to post Share on other sites
