Experiment with S. Aureus/Epidermis on Agar Plates

[saternet]

Hello there,

I am conducting an experiment on growing skin bacteria. For about 3 days, I incubated my streaked plates (informally streaked, I just swabbed it in a predictable pattern with a sterile applicator) at 20C for 72 hours. I saw no growth so I took it and incubated it since 35 hours ago (it is still being incubated) at about 35 - 39C. however, I am seeing a LOAD of condensation on my petri lids. Quite a bit of moisture is collecting on the lids (of course I incubated them upside down). I am using standard nutrient agar and incubated my plates right after the 20C incubation period. Is this normal, or preventable? I plan to incubate my plates for about 24 more hours. Will my agar dry out?

Thanks!

[saternet]

Hello there,

I am conducting an experiment on growing skin bacteria. For about 3 days, I incubated my streaked plates (informally streaked, I just swabbed it in a predictable pattern with a sterile applicator) at 20C for 72 hours. I saw no growth so I took it and incubated it since 35 hours ago (it is still being incubated) at about 35 - 39C. however, I am seeing a LOAD of condensation on my petri lids. Quite a bit of moisture is collecting on the lids (of course I incubated them upside down). I am using standard nutrient agar and incubated my plates right after the 20C incubation period. Is this normal, or preventable? I plan to incubate my plates for about 24 more hours. Will my agar dry out?

Thanks!

[Louise]

Hello there,

I am conducting an experiment on growing skin bacteria. For about 3 days, I incubated my streaked plates (informally streaked, I just swabbed it in a predictable pattern with a sterile applicator) at 20C for 72 hours. I saw no growth so I took it and incubated it since 35 hours ago (it is still being incubated) at about 35 - 39C. however, I am seeing a LOAD of condensation on my petri lids. Quite a bit of moisture is collecting on the lids (of course I incubated them upside down). I am using standard nutrient agar and incubated my plates right after the 20C incubation period. Is this normal, or preventable? I plan to incubate my plates for about 24 more hours. Will my agar dry out?

Thanks!

Post this on the life sciences forum, and search that forum for information on agar plates. I think someone ran in to a similar problem, and a biology expert answered it.

Louise