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Pantheist
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First Time Pouring Agar in a SAB - Exposed Petri Query
#23994438 - 01/09/17 05:50 AM (7 years, 21 days ago) |
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Hullo, I finished pouring some petri dishes / plates in the SAB, but butchered the bag they came in while opening it, so I couldn't store them back inside for protection. I left them in the SAB to cool overnight and then lifted the SAB to prepare for inoculation, leaving the closed plates exposed to the rooms air for about a couple of minutes. I also accidentally opened one in the open air and just threw it straight out - right thing to do right?I gave the remaining plates a wipe with IPA and now I'm letting the air settle in the SAB. I plan to parafilm the plates after inoculation, but I'm interested how likely the petri's are to have contamination now they've been left out.
I appreciate there are a lot of variables, so I'm interested in any scenarios people would like to put forward. In my case, I didn't clean the room beforehand, didn't spray the air with lysol, I'm not wearing a facemask but have done the usual spraying down the table with IPA, washed my hands then had a wipe with IPA, misted soapy water on the SAB walls, wiped the bits going inside the box with IPA beforehand, tried not to hover anything over the petri's while pouring etc.
I also noticed the petri's mist up after pouring which I understand to be bad, but at the same time the agar was a bit lumpy while coming out which would indicate it was too cold! Could it just be that the room temperature is too cold to be pouring petri and is causing the condensation? I've used MEA.
Oh, I was also wondering - I've used a thick wad of polyfil to act as a filter in the agar bottle for pressure cooking. How does this compare to a SFD? The bottle I used was a fantastic shape, but didn't have a screw top so I couldn't fit a SFD. Is polyfil ok?
Edited by Pantheist (01/09/17 06:39 AM)
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Psilosopherr
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Pantheist]
#23994480 - 01/09/17 06:36 AM (7 years, 21 days ago) |
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lumpy and causing steam/condensation? wtf
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PsilocyBen17
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Psilosopherr]
#23996828 - 01/09/17 10:26 PM (7 years, 21 days ago) |
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Pantheist
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: PsilocyBen17]
#23998910 - 01/10/17 05:49 PM (7 years, 20 days ago) |
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Well it turns out I got my agar / water ratio wrong - I came back to my zip-lock bag and found fluid floating round inside the petri's. I'm wondering whether this is what caused the condensation while being lumpy! Bit of a messy first attempt, will try again soon and post back results.
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Quadman
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Pantheist]
#23999050 - 01/10/17 06:42 PM (7 years, 20 days ago) |
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After my first pour. Now I always heat and mix the agar before sterilizing. Sometimes the agar settles to bottom making clumps and runny plates if not heated.
I leave plates out all the time in the winter unsealed. Usually not a problem unless you take the lid off. Not that it is recommended.
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Edited by Quadman (01/10/17 06:44 PM)
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PsilocyBen17
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Quadman]
#23999114 - 01/10/17 06:59 PM (7 years, 20 days ago) |
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what do you mean leave them out? You put them on your shelf unsealed?Quote:
Quadman said: After my first pour. Now I always heat and mix the agar before sterilizing. Sometimes the agar settles to bottom making clumps and runny plates if not heated.
I leave plates out all the time in the winter unsealed. Usually not a problem unless you take the lid off. Not that it is recommended.
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Quadman
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: PsilocyBen17]
#23999447 - 01/10/17 08:39 PM (7 years, 20 days ago) |
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Yes I have left plates unsealed, like I said not recommended.
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Pantheist
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Quadman]
#24000129 - 01/11/17 02:36 AM (7 years, 19 days ago) |
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Quote:
Quadman said: After my first pour. Now I always heat and mix the agar before sterilizing. Sometimes the agar settles to bottom making clumps and runny plates if not heated.
I leave plates out all the time in the winter unsealed. Usually not a problem unless you take the lid off. Not that it is recommended.
Thanks for your input. I did mix it in a pan beforehand, but perhaps not long enough.. It looked like it had all dissolved after stirring for just 30 seconds, and I kept going for about a minute or so total. I've been using MEA, if that makes any difference.
How long do you normally do it for before sticking it in for PC?
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PsilocyBen17
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Pantheist]
#24000345 - 01/11/17 06:48 AM (7 years, 19 days ago) |
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I heat my agar up on the stove and stir until it reaches a boil (not really a 'boil' persay, but it starts foaming up) then I take it off the stove and pour it into a bottle for a pour tek or pasty plates.
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Quadman
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: PsilocyBen17]
#24000474 - 01/11/17 08:23 AM (7 years, 19 days ago) |
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hot enough to set up after it cools then sterilize
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Pantheist
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Quadman]
#24000784 - 01/11/17 10:43 AM (7 years, 19 days ago) |
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Ah of course! Let it cool and set in the bottle, then deal with any excess liquid before the PC stage. Perfect!
Edited by Pantheist (01/11/17 10:46 AM)
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Quadman
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Pantheist]
#24000929 - 01/11/17 11:43 AM (7 years, 19 days ago) |
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There should be no excess fluid if you follow a Tek and have a good scale. Once solidified you can heat over and over to make more pours.if you reheat you may need to add water.
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PsilocyBen17
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Re: First Time Pouring Agar in a SAB - Exposed Petri Query [Re: Quadman]
#24001159 - 01/11/17 01:18 PM (7 years, 19 days ago) |
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there shouldnt be any access water. The only problem ive had is that the agar sometimes clumps up and doesnt mix well. This is why i start with cold water and mix the shit outta it. If i start with warm water it sometimes clumps
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