Incubating Agar Plates.
Incubating Agar Plates.
Dear All - Having a lot of trouble with condensation falling onto the lid of the petri dish containing the Agar (I incubate the plates upside down the idea being to prevent the condensation falling onto the agar) But I seem to have an awful lot of condensation - is there any way I can prevent this or reduce the amount? Your input would be appreciated. Cheers. Judygee.
-
rae
- Posts: 1045
- Joined: 31 May 2006, 10:00
- School: Oxley College
- Suburb: Burradoo
- State/Location: NSW
Incubating Agar plates
Hi There!!
I've also read somewhere that you can dry the plates in an incubator at 30degrees overnight. This also checks for contamination. I haven't tried this myself.
Good Luck
Lorrae
I've also read somewhere that you can dry the plates in an incubator at 30degrees overnight. This also checks for contamination. I haven't tried this myself.
Good Luck
Lorrae
Hi Judy,
I found the following on a site the other day. I haven't tried it myself. Of course there is a chance of contamination of the plates....but it may be of use to you anyway. Hope this helps!
http://www.science-projects.com/PlateDrying.htm
How to Dry Agar Plates Aseptically
(This procedure will take about one hour.)
1. You have already poured your plates, and have possibly stored them right-side up (Fig 1 and not like in Fig 2) in the refrigerator. By now lots of condensation has accumulated in them that must be aseptically removed.
Orientation of Plates
2. Find a countertop that is free of drafts and insects (ants, flies, roaches, etc.) which like to walk around on the agar surfaces with their dirty feet.
3. You need a nearly sterile surface. Here's a cheapie way to make one. Consider a fresh roll of paper towels. The paper inside is essentially sterile due to its hot, untouched, manufacturing process.
4. Touching only the edges or the outside surface, unroll a length of paper towels, and lay these out on your countertop such that the inner surface is up. Voila: a sterile surface!
5. Place a prop such as a pencil down on the paper towel near the end.
6. Next open one plate at a time and set them one on the other as shown in Fig 3. Their openings MUST be pointing downwards so that dust will not settle in them. (If the covers have lots of moisture, fling off the excess by holding the cover tightly and giving it a quick flick of the wrist. Don't do this with the agar-filled bottoms unless you want to clean up a mess!)
Drying the Plates
7. When you no longer see liquid on the inside of the covers and on the agar surfaces, put the plates together and stack them right side up (Fig 1). (This prevents dust from falling into the joint. Were the plates stacked upside down (Fig 2), any dust that falls into the joint would then slip inside and, when the plate is turned over to use, would then fall onto the agar surface. Mold will most certainly grow.
Only once inoculated* are plates stored upside down (Fig 2).)
I found the following on a site the other day. I haven't tried it myself. Of course there is a chance of contamination of the plates....but it may be of use to you anyway. Hope this helps!
http://www.science-projects.com/PlateDrying.htm
How to Dry Agar Plates Aseptically
(This procedure will take about one hour.)
1. You have already poured your plates, and have possibly stored them right-side up (Fig 1 and not like in Fig 2) in the refrigerator. By now lots of condensation has accumulated in them that must be aseptically removed.
Orientation of Plates
2. Find a countertop that is free of drafts and insects (ants, flies, roaches, etc.) which like to walk around on the agar surfaces with their dirty feet.
3. You need a nearly sterile surface. Here's a cheapie way to make one. Consider a fresh roll of paper towels. The paper inside is essentially sterile due to its hot, untouched, manufacturing process.
4. Touching only the edges or the outside surface, unroll a length of paper towels, and lay these out on your countertop such that the inner surface is up. Voila: a sterile surface!
5. Place a prop such as a pencil down on the paper towel near the end.
6. Next open one plate at a time and set them one on the other as shown in Fig 3. Their openings MUST be pointing downwards so that dust will not settle in them. (If the covers have lots of moisture, fling off the excess by holding the cover tightly and giving it a quick flick of the wrist. Don't do this with the agar-filled bottoms unless you want to clean up a mess!)
Drying the Plates
7. When you no longer see liquid on the inside of the covers and on the agar surfaces, put the plates together and stack them right side up (Fig 1). (This prevents dust from falling into the joint. Were the plates stacked upside down (Fig 2), any dust that falls into the joint would then slip inside and, when the plate is turned over to use, would then fall onto the agar surface. Mold will most certainly grow.
Only once inoculated* are plates stored upside down (Fig 2).)
-
Ocean Breeze
- Posts: 798
- Joined: 01 Jun 2006, 10:00
- Job Title: Lab Manager
- State/Location: NSW
Yep, all sounds good to me. I make sure my agar has cooled to 50 degrees C before pouring.The temp is the biggest factor.
Then stack them, one atop the other on the bench, 10-15 plates high. This allows them to cool very gradually, minimising condensation. When cooled & set, they can then be inverted and stored for use.R-S
Then stack them, one atop the other on the bench, 10-15 plates high. This allows them to cool very gradually, minimising condensation. When cooled & set, they can then be inverted and stored for use.R-S
Incubating Agar Plates.
Dear All (Louise, Lorrae, Helen, Kate, Liz and Rainbow-sky) - Thank you so much for your suggestions - of course I have been doing all the wrong things - pouring too hot, not warming petri dishes, not stacking plates etc.etc. I will use ALL your suggestions next time I'm preparing agar plates. Once again my thanks. Cheers. Judy.
Agar Plates.
Welcome back!! hope you all had a good break and are now ready to do it all again!!! Many Thanks to all who helped me out with the problem of condensation on agar plates - have since made a new batch following ALL your suggestions and had great success. Once again Many thanks. Judy.
