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blindspot61
Mr

Registered: 07/27/11
Posts: 48
Loc: Malaysia
Last seen: 7 years, 9 months
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How to recognize bacteria contamination?
#18080873 - 04/09/13 08:48 AM (10 years, 9 months ago) |
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Hi All, I used to understand that you can identify bacteria contamination in an agar by looking for some mushy white spot and it smell kind of sour.
Recently, I add a very small amount of yeast (1.5gm to 250ml of water) into my PDA. I sterilized it the same amount of time that I did for my PDA mixture.
The mycelium is growing quite well and it seems to be very clean without any traces of contamination, be it fungi or bacteria. My problem is after a couple of days, the agar with yeast emit a sour smell but i don't see any sign of bacteria contamination spot. Is bacteria contamination not necessary come in the form of mushy white spot?
I tried to transfer some part of the mycelium onto a different agar which is without yeast twice (meaning I cut a small piece of mycelium from the yeast agar and transfer it to another nonyeast agar and once it grow to a nice size, I cut it again to do another transfer to a non yeast agar) but the smell came back after a couple of days in the new disc.
I'm very frustrated because the mycelium that I have culture is growing very actively and I have to throw them away. . . . (its a grey oyster btw). 8 (
Need advise. Thank you in advance. . .
Edited by blindspot61 (04/09/13 08:55 AM)
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Kizzle
Misanthrope


Registered: 08/30/11
Posts: 9,854
Last seen: 4 hours, 40 minutes
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Re: How to recognize bacteria contamination? [Re: blindspot61]
#18081942 - 04/09/13 01:36 PM (10 years, 9 months ago) |
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Usually bacteria appears like a wet border around the mycelium.
You can search specifically for images with advanced search, it's helpful for finding stuff like that...

Edited by Kizzle (04/09/13 01:40 PM)
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TranscendingLife
I Don't Need a Life to Live



Registered: 06/09/10
Posts: 21,627
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Re: How to recognize bacteria contamination? [Re: Kizzle]
#18087197 - 04/10/13 01:59 PM (10 years, 9 months ago) |
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Smell & look. Grains will stall after a shake due to a bacterial infection.

-------------------- AMU: We Quickly Answer Questions Here "One must accept the probability of failure to experience the elation of success." - TranscendingLife “A man of genius makes no mistakes; his errors are volitional and are the portals of discovery.” - James Joyce
      How I Do EVERYTHING      "Your vision will become clear only when you can look into your own heart…. Who looks outside, dreams; who looks inside, awakes."- Carl Jung "Anything that can be done chemically can be done by other means."- William S. Burroughs "You are as dead now as you will ever be" - Seth
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blindspot61
Mr

Registered: 07/27/11
Posts: 48
Loc: Malaysia
Last seen: 7 years, 9 months
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Hi, Thank you, Kizzle & TranscendingLife for your comment. What puzzle me is that it only smell but no sight of slimy white spot or any abnormal spot indicating foreign object in my petri disc. The mycelium looks healthy and growing actively but the smell is particularly strong. I'm quite new in this having practicing culturing & growing mushroom for the past couple of years and this is the 1st time I encountering this. Is all 'sour' smell cause by bacteria contamination even though the disc looks clean? Thank you.
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TranscendingLife
I Don't Need a Life to Live



Registered: 06/09/10
Posts: 21,627
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Re: How to recognize bacteria contamination? [Re: blindspot61]
#18091608 - 04/11/13 11:55 AM (10 years, 9 months ago) |
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Most likely there's some bacterial contamination. However, you're using agar, so you can transfer away from it. I'd make several transfers from the supposedly contaminated plate. You should get at least one clean culture from there. Other than isolation, agar is great for cleaning cultures.
-------------------- AMU: We Quickly Answer Questions Here "One must accept the probability of failure to experience the elation of success." - TranscendingLife “A man of genius makes no mistakes; his errors are volitional and are the portals of discovery.” - James Joyce
      How I Do EVERYTHING      "Your vision will become clear only when you can look into your own heart…. Who looks outside, dreams; who looks inside, awakes."- Carl Jung "Anything that can be done chemically can be done by other means."- William S. Burroughs "You are as dead now as you will ever be" - Seth
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blindspot61
Mr

Registered: 07/27/11
Posts: 48
Loc: Malaysia
Last seen: 7 years, 9 months
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Hi TranscendingLife, That is exactly what I have done (as mentioned in my initial post). In the matter of fact I transferred twice making sure I cut a small piece of agar away from the center of the earlier transferred piece but the smell came back in the new disc after a couple of days when the mycelium grown to a nice size.
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Leper
Lurker



Registered: 08/10/12
Posts: 246
Last seen: 4 years, 10 months
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Re: How to recognize bacteria contamination? [Re: blindspot61]
#18106218 - 04/14/13 12:35 AM (10 years, 9 months ago) |
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I recognized my bacterial infection by darker spots and stunted myc growth.
It also smelled like sour cream & onion.

My only experience with bacteria.
-------------------- Leper is a fictitious entity using images supplied by google to mask his/her inability to form normal social habits within society.
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TranscendingLife
I Don't Need a Life to Live



Registered: 06/09/10
Posts: 21,627
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Re: How to recognize bacteria contamination? [Re: Leper]
#18118064 - 04/16/13 12:12 PM (10 years, 9 months ago) |
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You should be able to clean it up. Make sure to take samples from the leading edge of growth Away from the bacterial contamination. Between 1 & 2 o'clock is where I took the sample from this agar dish.
-------------------- AMU: We Quickly Answer Questions Here "One must accept the probability of failure to experience the elation of success." - TranscendingLife “A man of genius makes no mistakes; his errors are volitional and are the portals of discovery.” - James Joyce
      How I Do EVERYTHING      "Your vision will become clear only when you can look into your own heart…. Who looks outside, dreams; who looks inside, awakes."- Carl Jung "Anything that can be done chemically can be done by other means."- William S. Burroughs "You are as dead now as you will ever be" - Seth
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