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taters
french fried
Registered: 11/03/02
Posts: 82
Loc: the garden
Last seen: 18 years, 10 months
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oyster madness
#1436683 - 04/07/03 03:54 PM (20 years, 11 months ago) |
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I have a question about my oyster cultures. I'm relatively new to growing edibles so please bear with me. Several weeks ago I inoculated 6 jars of birdseed with sawdust spawn. The jars grew quickly and all 6 colonized completely. A few weeks later I inoculated a second set of 6 birdseed jars with agar wedges. The second 6 jars all fell to a wide variety of contamination. All 12 of the jars were prepared in an identical manner; all were inoculated in the same area under the same conditions. My first thought was that the agar culture was itself contaminated, even though the petri looked perfect. After some thought I came up withg a different hypothesis. Do you think it likely that the reason the first 6 did not contaminate was the speed with which it colonized? With the sawdust spawn I saw signs of even growth within 24 hours. With the agar wedges I did not see growth for at least 2 days, and the growth was only in the immediate area of the wedges. I'm wondering if the slower, uneven growth is what allowed the contams to get a foothold. If you've read this far I thank you for your patience and request your opinions.
Edited by taters (04/07/03 04:45 PM)
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zeronio
Stranger
Registered: 10/16/01
Posts: 2,349
Loc: Slovenia
Last seen: 7 years, 6 months
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Re: oyster madness [Re: taters]
#1438133 - 04/08/03 12:50 AM (20 years, 11 months ago) |
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Your hypothesis could be correct - there were many more inoculation points with sawdust spawn and it's possible that it overgrew the contaminants. With agar wedges on grain is usually like that: after few days you get growth only around the wedges and then you shake the jar to get more growing points. There are several possibilities why you failed. If the culture looked perfect then it's more likely that the jars were not properly sterilized or you introduced contaminants with the inoculation. Increase sterliziation time, use peroxide (H2O2) or if you used it, use more.
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taters
french fried
Registered: 11/03/02
Posts: 82
Loc: the garden
Last seen: 18 years, 10 months
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Re: oyster madness [Re: zeronio]
#1453514 - 04/12/03 07:51 PM (20 years, 11 months ago) |
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Thanks zeronio.
I tried again with the same oyster cultures. Rather than removing the lids from the birdseed jars to introduce the agar wedges (as I did last time), I injected the jars using the following process:
I placed the agar wedges in a shot glass and added some 3% h2o2. I used my scalpel to mince the wedges as small as possible and then sucked the resulting solution into a syringe. A lot of the agar was left behind, but I assumed that some of the mycelia was in the solution. My thought was that the h2o2 would kill any contams without seriously damaging the mycelia culture.
Well, I injected the solution into my jars and the result was less than perfect. None of the injected jars contaminated, but none of them grew mycelia either. Is 3% h2o2 straight from the bottle too strong?
This would be so much simpler if I could afford to build a flow hood. Do you think that working in front of an operating HEPA filter would help cut contams? I found one for $50 at Sears.
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r05c03
The Slug Scourge
Registered: 01/06/02
Posts: 383
Loc: Indiana, US
Last seen: 18 years, 11 months
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Re: oyster madness [Re: taters]
#1453584 - 04/12/03 08:31 PM (20 years, 11 months ago) |
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Yeah, I'd agree with Z-, but if all six jars contaminated then you have problem with your sterilization, or you are introducing alot of cotams during inoculation.
How long have you waited to see growth from your attempt at liquid inoculation? I have found that it takes alot longer to see growth resulting from liquid inoculation than from other techniques. If you do not have contams wait on them a few more days to see. The way you described your technique makes me think that you may have gotten very little mycelia in the syringe. You probably got some, but it will take awhile to see if it grows out. I am not sure about the peroxide. I have not tried that tecnique.
-------------------- Listen! Do you smell something?
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NoLogos
newbie
Registered: 02/28/03
Posts: 37
Loc: South US
Last seen: 20 years, 25 days
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Re: oyster madness [Re: r05c03]
#1458325 - 04/14/03 08:14 PM (20 years, 11 months ago) |
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I have inoculated oysters on straw using agar wedges shaken up in sterile water, then dumped on pasteurized straw. I'll bet the H2O2 was the culprit--it must have burned the broken ends of the mycelia or something. Oysters grow so fast!
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