Disposable Petries, PC'able??

[punkin]

Can't find any info on my dishes, but just wondering if people re-use em or not?

I poured twenty or so with some agar that didn't go well with mycelium and although they were still noninfected, just wanna know if i was em with soapy bleach and rinse...the best way to resterilise em?

[The Deb-One-Amine]

im not sure but i know sterilising should do the job just make sure you clean them well.. could you chuck em into a dish washer or a bottle steriliser.

[shortly]

I soak other plastics in 10% bleach for a day or two prior to washing & don't usually have any issue with contamination.

Even a trip through with the brew bottles n gear would probably do.

[gerbil]

Don't PC them lol melty melty. maybe there are different grades, i remember one fella talking through a tek and he was pc-ing them from memory, i was a bit confused but thought i'd give it a go, and with my plates it wasn't good ;)

Re-using is a good idea if you want to get the most out of the resource, if you do clean them up and go to re-use, h202 in the agar can be a help, as well as aggressive cultures.

I've never used them, am sorta interested, maybe one day, might be worth looking into glass plates if you want to constantly re-use :D

I don't re-use them, i don't really like wasting resources, but i've been running from a single box for many years and still have a fair few sleeve left, the cultures go a long way and I only start new sleeves for mass prop, re-invigorating cultures or starting new lines.

Edited August 14, 2010 by gerbil

[punkin]

K, thanks guys. I have a LOT of alchohol, so may just soak em in some 70% and then put em in bags, should do the trick ok.

[Magicdirt]

Acidified bleach kills bacteria better than anything I know of.

below is from an interview with Norman Miner, a researcher at microchemlam.net

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Adding white vinegar to diluted household bleach greatly increases the disinfecting power of the solution, making it strong enough to kill even bacterial spores. Researchers from MicroChem Lab, Inc. in Euless, Texas, report their findings today at the 2006 ASM Biodefense Research Meeting.

Sodium hypochlorite (NaOCl) in the form of laundry bleach is available in most households. The concentrate is about 5.25 to 6 percent NaOCl, and the pH value is about 12. Sodium hypochlorite is stable for many months at this high alkaline pH value.

"Laundry bleach is commonly diluted about 10 to 25-fold with tap water to about 2000 to 5000 parts per million of free available chlorine for use as an environmental surface disinfectant, without regard to the pH value of the diluted bleach. However, the pH value is very important for the antimicrobial effectiveness of bleach," says Norman Miner, a researcher on the study.

At alkaline pH values of about 8.5 or higher, more than 90 percent of the bleach is in the form of the chlorite ion (OCl-), which is relatively ineffective antimicrobially. At acidic pH values of about 6.8 or lower, more than 80 percent of the bleach is in the form of hypochlorite (HOCl). HOCl is about 80 to 200 times more antimicrobial than OCl-.

"Bleach is a much more effective antimicrobial chemical at an acidic pH value than at the alkaline Ph value at which bleach is manufactured and stored. A small amount of household vinegar is sufficient to lower the pH of bleach to an acidic range," says Miner.

Miner and his colleagues compared the ability of alkaline (pH 11) and acidified (pH 6) bleach dilutions to disinfect surfaces contaminated with dried bacterial spores, considered the most resistant to disinfectants of all microbes. The alkaline dilution was practically ineffective, killing all of the spores on only 2.5 percent of the surfaces after 20 minutes. During the same time period the acidified solution killed all of the spores on all of the surfaces.

"Diluted bleach at an alkaline pH is a relatively poor disinfectant, but acidified diluted bleach will virtually kill anything in 10 to 20 minutes," says Miner. "In the event of an emergency involving Bacillus anthracis spores contaminating such environmental surfaces as counter tops, desk and table tops, and floors, for example, virtually every household has a sporicidal sterilant available in the form of diluted, acidified bleach."

Miner recommends first diluting one cup of household bleach in one gallon of water and then adding one cup of white vinegar.

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Sorry for the long post but this stuff is awesome.

[yaguareté]

Polystyrene dishes are def not pc'able. SOME polypropylene dishes are

Glass def are.

[punkin]

Thanks magicdirt. I did wash em in bleach water with a long soak (even though they were clean) but then i have the problem of rinsing.

Do you have a solution to that? Maybe just boiling them in some rince water?

I've had them outside drying in the sun, i think i'll just give em a spray with 80% ethanol before i repackage them, at least the ethanol will evaporate to leave a clean, sterile dish.

Would still be nice to know a good method for next time though.

[punkin]

Think i've found the answer. Here of course

Was just continuing my perusal of all the past posts in Mycology Forum (i'm up to about page 30 in the history) when i found this about microwave pc'ing plastic vessels, specifically dishes

http://www.shaman-australis.com/forum/index.php?showtopic=11591

Links to this page..

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC242123/?tool=pubmed

That says it works great

edit; Just tried it, seemed to work great, dishes came out cold and hopefully sterile

Edited August 14, 2010 by punkin

[tripsis]

I recommend using PP plastic food containers, the same as the ones that I sent you cultures in punkin. They are autoclavable and thus reusable, as well as being recyclable, something that PS is not. Because you can autoclave them, you can recover contaminated plates too, by sterilising them with the contaminants inside, then cleaning them out.

You can buy them here and the corresponding lids here. You can also buy cartons of 1000 if needed.

[punkin]

Thanks mate, i've been meaning to ask where you got them. I like the way the lids snap on too

Lot cheaper than the disposable petries as well.

Anyone want to buy a nearly full box of individual gamma 90 mm petries?

[GoOnThen]

Damit......I thought the plates you use Tripsis were PS I have already chucked two out

Thanks for the link I will by some when I use up the rest of my PS petri sleeves

Cheers

Got

[yaguareté]

Damn there cheap tripsis. I much prefer the idea of being able to pour the plates and then autoclave them again.

[punkin]

Managed to find em locally for a couple of dollars a hundred. they go fine in the pressure cooker too.

Heaps of plastic individual sealed gamma sterilised 90mm petries for sale cheap if anyone wants em

[shortly]

how much do you want for the dishes??

Your maitake plates havin a sulk but as soon as it pick up i'll post it off

[punkin]

how much do you want for the dishes??

Your maitake plates havin a sulk but as soon as it pick up i'll post it off

 

I'll get the box out and see how many dishes are left. I'll see if i can figure out what i paid for em and they're yours for that, less what i used.

[mysubtleascention]

Even if contaminated I reuse the plastic petri dishes ..wash with a detergent, let dry.. then right before pouring the PDA - peroxide agar .. i cotton swab the insides of both upper and lower parts, first with peroxide(3%),then with ethanol 95% .When the agar is poured and cold - wrap the whole thing with plastic wrap ..Lasts for months at room temp..

I haven't tried this with plain (unperoxidized) agar though ..

cheers

B.

Edited February 14, 2012 by mysubtleascention

[NSF]

It depends on the strength of peroxide you've got.

The local hair supply place had peroxide in about 4 or 5 strengths.

[mysubtleascention]

10 - 15 ml (3%)peroxide for 1 liter of hot( 50 Celsius) agar liquid ..

(the agar solution should be slightly denser than the usual, due to the peroxide liquid dilution.. )

Edited February 14, 2012 by mysubtleascention