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gt40
I will proof smthng



Registered: 09/17/12
Posts: 502
Last seen: 8 days, 19 hours
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Anybody here have contam in petri dishes before inoculation?
#18922490 - 10/02/13 05:14 PM (10 years, 3 months ago) |
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 It happened for a few times. I took my dishes from PC and put it in a plastic bag. One day later when I want to start inoculation, I saw contam on agar in all petri dishes. I have no problems with sterilization before.
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Habadashery



Registered: 10/05/10
Posts: 937
Loc: Washington State
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Re: Anybody here have contam in petri dishes before inoculation? [Re: gt40]
#18922570 - 10/02/13 05:30 PM (10 years, 3 months ago) |
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ONE day later? Oye!
Don't know. Even if you didn't PC it long enough or hot enough, I would think it would take more than ONE day to contam.
Hmm.
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SpitballJedi
Ancient Astronaut



Registered: 10/13/12
Posts: 8,598
Loc: Nibiru
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Re: Anybody here have contam in petri dishes before inoculation? [Re: gt40]
#18922725 - 10/02/13 06:08 PM (10 years, 3 months ago) |
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I presume you are using glass dishes since you said you took petri dishes from the PC.
On a highly nutritive media, molds can grow pretty quick, but one day is fast.
What tek are you following?
I don't trust the glass ones because I don't feel like I can keep them sterile from PC to storage.
The bags should be brand new ziplocks.
Quote:
gt40 said:
 I have no problems with sterilization before.
When we do things imperfect, sometimes we still get great results, sometimes for a great while even. Only when we run in to problems do we realize we can make improvements to get consistent great results. The devil is in the details.
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RogerRabbit
Bans for Pleasure



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Re: Anybody here have contam in petri dishes before inoculation? [Re: gt40]
#18923116 - 10/02/13 07:52 PM (10 years, 3 months ago) |
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You're supposed to sterilize the agar in a bottle and then pour it later. If you're using glass petri dishes, just stick them in the PC empty while you sterilize the agar. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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rumfor69
Bodhicitta Cultivator



Registered: 08/05/11
Posts: 6,767
Loc: In the Gills
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Re: Anybody here have contam in petri dishes before inoculation? [Re: RogerRabbit]
#18923428 - 10/02/13 09:12 PM (10 years, 3 months ago) |
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When you pour agar how would you sterilize plastic petri dishes before hand?
Or do you just buy them pre-sterilized?
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PussyFart
Retired Cultivation Extrodinaire



Registered: 04/08/12
Posts: 22,502
Loc: Orbiting Earth
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Re: Anybody here have contam in petri dishes before inoculation? [Re: rumfor69]
#18923435 - 10/02/13 09:13 PM (10 years, 3 months ago) |
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Quote:
rumfor69 said: you just buy them pre-sterilized
--------------------
THIS HOBBY IS NOT FOR THE IMPATIENT! PLEASE BE PATIENT, DON'T BE A PATIENT! A Tale of 10 Isolates, GT Cluster Clone Monotubs, RR's Let's Grow Mushrooms DVD, SGFC(Shotgun Fruiting Chamber), Monotub Tek, Damion5050's Coir Tek, TL's Tek List, Frank's Tek List, EvilMushroom666's Pasteurization Tek, How It Should & Shouldn't Look - NEW CULTIVATORS GUIDE *** *** AFGHAN KUSH GROW LOG *** ***
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rumfor69
Bodhicitta Cultivator



Registered: 08/05/11
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Re: Anybody here have contam in petri dishes before inoculation? [Re: PussyFart]
#18923450 - 10/02/13 09:16 PM (10 years, 3 months ago) |
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Quote:
Notahacker420 said:
Quote:
rumfor69 said: you just buy them pre-sterilized
Thats what i figured i just had to ask LOL
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gt40
I will proof smthng



Registered: 09/17/12
Posts: 502
Last seen: 8 days, 19 hours
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Re: Anybody here have contam in petri dishes before inoculation? [Re: rumfor69]
#18924357 - 10/03/13 02:55 AM (10 years, 3 months ago) |
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Wow, thanks for fast responde! For sure I have used glass dishes. Every time A LOT of condensation inside after PC. Maybe it initiates contam, although I put them one by one. I think I will try to prepare the agar in the bottle separately next time.
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Habadashery



Registered: 10/05/10
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Loc: Washington State
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Re: Anybody here have contam in petri dishes before inoculation? [Re: gt40]
#18924920 - 10/03/13 08:19 AM (10 years, 3 months ago) |
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And really, using 1/4 or half pint jars with filter lids, is way more user friendly imo. Most of the petri dishes I tried to make in the past failed, just couldn't keep it together. For those of us without the steady hand, I would suggest agar in a jar. Haven't had but 1 fail in a jar so far, outta 20+
And its a great thing to do with those jars you used for PF tek, which you probably aint never gonna do again!
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Fred Teddy
Flying with Turkeys


Registered: 07/18/11
Posts: 208
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Re: Anybody here have contam in petri dishes before inoculation? [Re: Habadashery]
#18925149 - 10/03/13 09:48 AM (10 years, 3 months ago) |
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Quote:
Habadashery said: And really, using 1/4 or half pint jars with filter lids, is way more user friendly imo. Most of the petri dishes I tried to make in the past failed, just couldn't keep it together. For those of us without the steady hand, I would suggest agar in a jar. Haven't had but 1 fail in a jar so far, outta 20+
...
Petri's "vent" thats why you're supposed to seal it up with parafilm.
I do agar both ways but I like the no-pour agar in 1/4 pt jars. I use a lid seal side down with a large 3/4" hole in it to help the condensation escape. Seal side down because I always seemed to get contaminants around the edges. That stopped when I started using seal side down. Use whatever filter you want. I use tyvek held down with a ring magnet. Cover with foil and PC. Remove from PC, remove the foil, and let the jars cool. You will get little or no condensation. To store or keep from drying out, I put a piece of plastic bag over the filter and put the magnet back on. From here, once you determine a clean sample, you can continue to do agar work, or let go to 100% and add an LC or sterilized water for syringes, or do a sterilized grain to agar jar (tricky though, too much exposure). I like the LC approach, I can do more grain jars that way than just using the agar as wedges, and I know its clean. I know this is not "traditional" but a jar of myc has a lot of versatility imo.
Peace, FT
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Rauhfasertapete
The Final Cauliflower of Doom!



Registered: 02/22/13
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Re: Anybody here have contam in petri dishes before inoculation? [Re: gt40]
#18925275 - 10/03/13 10:31 AM (10 years, 3 months ago) |
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Quote:
gt40 said:
 One day later when I want to start inoculation, I saw contam on agar in all petri dishes.
I don´t think you can get visible contamination in one day. But I once had something that looked similar. I boiled potato peels together with baker´s yeast and fructose, and then let the starchy cooking water drip through a coffee filter. The resulting liquid was quite homogenous, and I used it for my agar which I then sterilised in the petri dishes. When it was solid again after PCing, I noticed that some kind of little spots (about a mm in diameter) have formed in the agar, especially on the bottom. They seem to have formed from starch or other small particles.
It still worked well, actually some of the finest agar I evervmade. It just didn´t look nice.
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36fuckin5
Alchemycologist


Registered: 08/11/03
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Loc: Diving into Mystical Territori...
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Re: Anybody here have contam in petri dishes before inoculation? [Re: Rauhfasertapete]
#18925644 - 10/03/13 12:25 PM (10 years, 3 months ago) |
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Quote:
Rauhfasertapete said:
Quote:
gt40 said:
 One day later when I want to start inoculation, I saw contam on agar in all petri dishes.
I don´t think you can get visible contamination in one day.
Of course you can. That's just silly.
OP, wrap your empty petris in foil and PC them, then pour them in a SAB or in front of a flowhood.
-------------------- Redd Foxx said: If you're offended I don't give a shit and don't come see me no more. Pat The Bunny said: A punk rock song won't ever change the world, but I can tell you about a couple that changed me. bodhisatta said: i recommend common sense and figuring it out. These are the TEKs I use. They're all as cheap and easy as possible, just like your mom.
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