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mobyd
mad agar worker


Registered: 03/27/02
Posts: 346
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Tons of contaminations WITH Flow Hood!!!
#1544660 - 05/13/03 09:30 AM (20 years, 8 months ago) |
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Hi Dudes!
I transferred Agarpieces to about 10 jars and 5 Petridishes. EVERYTHING is contaminated now but i used my flow hood and (96% and 70%) Alcohol. How could this happen???
I tell ya what i?ve done:
First of all I let the Flow Hood ran for about 5 minutes. I sprayed 70% Alcohol on in front of my flow hood to desinfect the table. Then I put a scalpell in a jar (filled with 96% Alcohol). When transfer agarpieces to a jar I unscrewed on the lid til i?m able to remove the Lid and spray Ethanol on it (to be sure theres no contamination on the jar). Then I take my scalpell and ignite it (due to the Ethanol it burns for a short while and the it expires) to use. I cut pieces (~,5-1cm?) and put it into the jar/Agarplate.
Please don?t tell me to check if the filters ok, I know it is cause I tested it with an Agarplate.
PLease help, what it could be (I heard the room humidity could be to dry)????
mobyd
-------------------- Sorry, my english is really bad! If you like my work, rate me....
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MycoFactory
Mr MycoBag

Registered: 04/02/03
Posts: 549
Loc: NC, USA
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Re: Tons of contaminations WITH Flow Hood!!! [Re: mobyd]
#1544768 - 05/13/03 10:19 AM (20 years, 8 months ago) |
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There may be latent ungerminated contaminate spores on your master plate. Try the transfer again, this time turning the transfer wedges upside down on the new plate. Failing that you can try pouring semi-cooled agar over the transfered wedges. This may smother the contaiminate allowing for the mycelium to grow out. Further transfers will be needed to get a clean culture from both of these methods. Also always be aware of your movements in front of the hood to be sure the contaminates are not blowing off your hands on to the plates. Hope you can save your cultures.
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SixTango
Mycota

Registered: 01/21/02
Posts: 1,996
Loc: A little North of Paradis...
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Re: Tons of contaminations WITH Flow Hood!!! [Re: mobyd]
#1544789 - 05/13/03 10:30 AM (20 years, 8 months ago) |
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Just a thought & a maybe . First flow hood my foaf built was flat faced on the filtered air exit end. He still got some contams, now & again. Puzzle puzzle puzzle....... Turns out, the air flow was not laminar, except directly at the face of the filter. Working a bit further back, there was a vortex effect, which drafted in unfiltered air from beside the filter. Foaf boxed in the face open ended, with one end screwed to the filter case. That created a 24 X 24 inch work area where the air flow as laminar. Problemo resolved. 6T
-------------------- ~whiskey river rafting, hot tubbing, dirty dancing & spending money on - wild women - having fun & just gonna waste the rest~
Edited by SixTango (05/13/03 10:31 AM)
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calicyco
member
Registered: 05/03/03
Posts: 355
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Re: Tons of contaminations WITH Flow Hood!!! [Re: SixTango]
#1545189 - 05/13/03 01:02 PM (20 years, 8 months ago) |
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You aren't flame sterilizing your scalpel for one thing. Just lighting it on fire isn't doing anything, even after soaking in alcohol. That is not a true disinfectant. You need to heat it until its red hot and then only touch sterile surfaces. Only if its is glowing red has it been sterilized. If you are going to chemically sterilize it you need to use a sterilizing solution. Ethanol isn't a medical/lab grade sterilizer.
The filter itself isn't the problem perhaps, but it is coming from somewhere. You might be creating disturbances in the air. Check every stage of the process via control measures. TMC has some good info on how to narrow down contaminant causes.
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FungusmaximusFM
Shepherds theweak through thevalley ofdarkness

Registered: 05/20/03
Posts: 220
Loc: The Netherlands
Last seen: 18 years, 12 days
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Re: Tons of contaminations WITH Flow Hood!!! [Re: calicyco]
#1563119 - 05/20/03 01:55 PM (20 years, 8 months ago) |
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my flowhood construction A good tip: Wear a new plastic rain poncho w/ hood when working under the flowhood. You can lysol the plastic poncho as needed. This will prevent any contam spores you are carrying on your skin/clothing from swirling back into your cultures. Do you have a face shield on your hood? I hinged some glass in a wooden frame and added some adjustable tripod legs to make the glass shield able to open and close on the front of the hood.
-------------------- Lord Fungusmaximus
Edited by FungusmaximusFM (05/20/03 02:05 PM)
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cyankid
newbie
Registered: 10/19/00
Posts: 49
Last seen: 13 years, 1 month
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Re: Tons of contaminations WITH Flow Hood!!! [Re: FungusmaximusFM]
#1563877 - 05/20/03 07:31 PM (20 years, 8 months ago) |
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I've always wondered if a glass "sneeze shield" would create non-laminar flow. Seems like the flow would hit it, then swirl back. I could be wrong, but then again I've never seen a professional flow hood with a sneeze shield. Anyone know for sure? Maybe a ciggarette or burning incense could tell.
cyankid
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