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German Kahuna
Facepalmer of Stoopid
Registered: 10/31/08
Posts: 15,798
Loc: On a Chemical Vacation
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Petri dish question
#9522540 - 12/31/08 07:54 AM (15 years, 2 months ago) |
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Hi, I used glass petri dishes before. The bigger ones (100x20mm, or so), but I didn't really find them to be ideal, because my hands aren't really big and when I tried picking them up and wrapping them with parafilm very often the lid would slip off a bit or the bottom would drop down. They are also quite heavy, which doesn't help much. Not ideal, really. So I bought some PE throw-away dishes like these:
The question is: it doesn't say that they were packaged sterile and since they'll start deforming at 80° Celsius, they can't be autoclaved either... Is it safe to pour the agar into them right after taking them out of their package without further measures or am I embarking the contamination ?
-------------------- "Vegetarian" [ /ˌvedʒəˈteəriən/] - Ancient slang meaning "village idiot who can't hunt, fish or ride".
Edited by German Kahuna (12/31/08 08:40 AM)
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Damion5050
Mush Doctor
Registered: 05/01/08
Posts: 12,493
Loc: Lost In Translation !
Last seen: 3 years, 1 month
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Probably not, hard to say..
Next time get them from here, this is where I purchase them from.
DISPOSABLE COMPACT PETRI DISH, 15x60mm, STACKABLE, 20/PK are $2.95
DISPOSABLE PETRI DISH, 15x100mm, STACKABLE, 25/PK are $4.40
They assure sterility, if you have a problem they will send you more..
http://cynmar.com/SearchByCategory.aspx?CategoryCode=331
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German Kahuna
Facepalmer of Stoopid
Registered: 10/31/08
Posts: 15,798
Loc: On a Chemical Vacation
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Re: Petri dish question [Re: Damion5050]
#9522641 - 12/31/08 08:37 AM (15 years, 2 months ago) |
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Well, what surprises me is: what's the bloody point in selling petri dishes that you can't sterilize and that don't come sterile either? What are they supposed to be used for then? Regarding the supplier you mentioned... I try to avoid ordering overseas, because shipping and customs are a real bitch. I know where I can get sterile ones here. I was just surprised to see that these ones I ordered didn't say that they were explicitly. Maybe I'll try the small glass ones next time. At least I know I can PC them properly.
-------------------- "Vegetarian" [ /ˌvedʒəˈteəriən/] - Ancient slang meaning "village idiot who can't hunt, fish or ride".
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denger
Mycelium keeper
Registered: 09/19/08
Posts: 1,177
Loc: Unites States of Dreams
Last seen: 1 year, 5 months
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I am yet to see a non-sterile pack of plastic dishes sold. Pour them and wait a couple of days, if nothing grows then you'r good.
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German Kahuna
Facepalmer of Stoopid
Registered: 10/31/08
Posts: 15,798
Loc: On a Chemical Vacation
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Re: Petri dish question [Re: denger]
#9522666 - 12/31/08 08:47 AM (15 years, 2 months ago) |
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That's what I was figuring as well. I was just irritated that it didn't explicitly say so on the packaging.
-------------------- "Vegetarian" [ /ˌvedʒəˈteəriən/] - Ancient slang meaning "village idiot who can't hunt, fish or ride".
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Damion5050
Mush Doctor
Registered: 05/01/08
Posts: 12,493
Loc: Lost In Translation !
Last seen: 3 years, 1 month
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My fault I was not paying attention to your location.. Or as some people would would say I was being the "typical american and I assume everyone lives in america". Some one was angry with me and told me that.. LoL
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 1 year, 29 days
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Re: Petri dish question [Re: Damion5050]
#9523094 - 12/31/08 10:49 AM (15 years, 2 months ago) |
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They're sterile in the package. Don't take them out of the plastic sleeve until you're in front of a flowhood or glovebox. 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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Jonat
Stranger
Registered: 12/30/08
Posts: 135
Last seen: 13 years, 9 months
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Re: Petri dish question [Re: RogerRabbit]
#9570743 - 01/08/09 12:49 PM (15 years, 2 months ago) |
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Anyone reuse plastic petri dishes after sterilizing with isopropanol? I know that some will say that these dishes are not so expensive to start with, but I strive to be cheap thrifty.
I came across one patent about sterilizing medical equipment with isopropanol vapor - should be even easier with a soak.
http://www.freepatentsonline.com/4282179.html
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frankenstoen
Registered: 01/26/08
Posts: 385
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Re: Petri dish question [Re: Jonat]
#9573319 - 01/08/09 08:07 PM (15 years, 2 months ago) |
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Quote:
Jonat said: Anyone reuse plastic petri dishes after sterilizing with isopropanol? I know that some will say that these dishes are not so expensive to start with, but I strive to be cheap thrifty.
I met a guy who uses heavy-duty peroxide to re-sterilize plastic petris with great success. I think you need a flow hood to dry them, though, otherwise they will quickly re-contaminate.
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MycoAu
5thKingdomCome
Registered: 07/18/07
Posts: 1,047
Last seen: 3 years, 2 months
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You can purchase 35% peroxide for use as a sterilant. I would recommend buying a lower percentage or going with a peracetic acid sterilant (safer). However, using glass petris will save you time and allow greater versatility in the lab in the long run. You can easily use one or two at a time versus opening a full pack of plastic petris and being forced to waste them or pour ~a liter of agar and store the rest. Don't use bleach to nuke the plates- it will leave a caustic residue that is harmful and is likely to cause mutations, etc. in young mycelium.
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 42,214
Loc: Seattle
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Re: Petri dish question [Re: MycoAu]
#9574330 - 01/08/09 10:20 PM (15 years, 2 months ago) |
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With disposable dishes, you open the sleeve to remove only as many dishes as you need, and then reseal the sleeve. It should go without saying it's done in front of a flowhood or in a glovebox. 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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MycoAu
5thKingdomCome
Registered: 07/18/07
Posts: 1,047
Last seen: 3 years, 2 months
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Re: Petri dish question [Re: RogerRabbit]
#9575698 - 01/09/09 06:27 AM (15 years, 2 months ago) |
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Apparently I'm behind the times. I had no idea about the resealable packaging (for petris). The dishes I use come prepared, so I don't mess with this stuff very often and all of the packages I've seen are single-use.
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German Kahuna
Facepalmer of Stoopid
Registered: 10/31/08
Posts: 15,798
Loc: On a Chemical Vacation
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Re: Petri dish question [Re: MycoAu]
#9575832 - 01/09/09 07:34 AM (15 years, 2 months ago) |
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I've ordered pre-poured petris from one of my mycosuppliers before and they all arrived as a mess. I don't know what happened to them during shipping. Fact is that the agar had liquefied in all the dishes. I contacted the supplier and he said that the agar on all of them was solid when he sent them out. So he reshipped. Same thing happened again. So I just went back to pouring my own. It's not that much of a deal.
-------------------- "Vegetarian" [ /ˌvedʒəˈteəriən/] - Ancient slang meaning "village idiot who can't hunt, fish or ride".
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SuchSmartMonkeys
mycologically driven individual
Registered: 10/26/05
Posts: 1,154
Last seen: 3 years, 20 days
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yeah, i wouldn't trust pr-poured plates. If they came in the plastic sleeve, they should be sterile. If they weren't there would be no purpose to them (what are you going to use unsterile petris for?). and to MycoAu, the packages usually aren't resealable. Either roll the extra plastic down and tape it shut, or if you have an impulse sealer, there you go...
and whoever said to pour them and wait, that's a good plan. Usually when i pour plates in my glovebox, i like to parafilm them and wait a couple days, or if i am planning on using them that day, i will pour a few extra plates than i need, and seal them up. It's good comparison for if contams start showing up, helps to deduce where the problem came from (you know whether you were fucked outright from the start, or if the contams came from something you added...)
-------------------- [url=http:
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German Kahuna
Facepalmer of Stoopid
Registered: 10/31/08
Posts: 15,798
Loc: On a Chemical Vacation
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They came from a mycosupplier in a sterile sleeve and wrapped with some lab film, so that wasn't my concern. The problem was the liquefied agar that was oozing out of the dishes and through the film wrapping (so it wasn't parafilm, that would have held back the goo).
-------------------- "Vegetarian" [ /ˌvedʒəˈteəriən/] - Ancient slang meaning "village idiot who can't hunt, fish or ride".
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