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celticcelery
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Registered: 12/11/18
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Help with constant contaminations
#26489131 - 02/16/20 09:56 PM (4 years, 6 hours ago) |
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 Hi everyone!
I have been having issues with getting this black contamination on all my agar dishes lately for the past few months. I was wondering if anyone has ever dealt with an issue like this. Before I never got contaminations on my grows; however, ever since my first contamination I've been getting this same black contam on my older dishes, but not newer dishes that I purchase. Does anyone know what contamination this is or suggest advice for a fix? Smiley Face contam, Thanks
Edited by celticcelery (02/16/20 10:13 PM)
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MrBovineJoni
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Registered: 11/28/19
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Re: Help with constant contaminations [Re: celticcelery]
#26489342 - 02/17/20 02:38 AM (4 years, 1 hour ago) |
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(I made an assumption that you are talking about glass petri plates, as I understood the way you are talking about old and new plates that you keep reusing them - which normally only is done with glass plates and not the metal ones).
So it happens with your old reused dishes repeatedly... and your brand new ones are fine. What does this tell you?
I immediately thought about 2 things : a) either you don't clean/sterilize them properly and the contamination carries on b) you have this contamination in some of your environment and somehow it latches onto your older plates that should have been sterilised (at home, I presume); while the new ones already come enclosed and pre-sterilised.
How do you make sure that the old contaminated plates are sterilised before using them again? And they stay sterile until they are poured with clean agar again?
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celticcelery
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Re: Help with constant contaminations [Re: MrBovineJoni]
#26489944 - 02/17/20 12:42 PM (3 years, 11 months ago) |
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The plates are pp (polypropylene) which has a heat tolerance up to 200C.
I pre-sterilize the contaminated plates at 17 psi for 30-45 minutes. Then I wash out the plates and reuse them.
Yes I came to that speculation as well. I am going to test this claim by sterilizing and pouring some agar (no pour tek) in my sab and open perform an empty inoculation.
Open the plates in the SAB with my normal protocol and then transfer the plates in my storage and see if any contamination presents itself in a month.
If there is no contamination then that means my spore syringes are the culprit.
Edited by celticcelery (02/17/20 12:44 PM)
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MrBovineJoni
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Re: Help with constant contaminations [Re: celticcelery]
#26490032 - 02/17/20 01:29 PM (3 years, 11 months ago) |
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Quote:
celticcelery said: I pre-sterilize the contaminated plates at 17 psi for 30-45 minutes. Then I wash out the plates and reuse them.
Did I get this right - you PC them and them you wash them in open air? That is what contaminates them after; they lost sterility as soon as you washed/opened them.
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celticcelery
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Re: Help with constant contaminations [Re: MrBovineJoni]
#26490085 - 02/17/20 02:03 PM (3 years, 11 months ago) |
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Yes that is how I clean them.
When I reuse them for use I pour agar into them and then do a PC cook for 30 minutes at 15 psi (with a 10 minute vent)
Then I let it cool overnight before bringing them to use in my SAB
Edited by celticcelery (02/17/20 02:22 PM)
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MrBovineJoni
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Re: Help with constant contaminations [Re: celticcelery]
#26490360 - 02/17/20 04:00 PM (3 years, 11 months ago) |
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Oh I see, that makes sense. Well, I still reckon the contamination comes somewhere between the last PC (at some point after taking taking them out).
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celticcelery
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Re: Help with constant contaminations [Re: MrBovineJoni]
#26490541 - 02/17/20 05:35 PM (3 years, 11 months ago) |
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I agree.
I am going to try doing an empty inoculation
Prepare my inoculation as usual. But instead of innoculating with a spore I will just open the petri dish for a few seconds, make a few air movements with my hands and then wrap the dish. I will wait a month to see if any of the same contamination still forms.
Hopefully that will tell me if my petri dishes or spore syringes are the culprit.
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