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 Tolerated
Master Contaminant Grower
 
Registered: 04/17/10
Posts: 171
Loc: The Ass crack of Nowhere....
Last seen: 2 years, 2 months
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 Re: Steralizing Plastic Petri Dishes  [Re: fungus_tao]
#12868773 - 07/08/10 05:25 PM (12 years, 10 months ago) |
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Plastic dish = disposable
Glass dish = reusable
Plastic dishes preform horribly to sterilizing teks.....
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Cheers Tolerated.
Keeper's Creeper's where did you get that smile.....
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 ambargh
Registered: 08/15/09
Posts: 3,433
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868777 - 07/08/10 05:25 PM (12 years, 10 months ago) |
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Ummm... 8 yr old thread guys... Just sayin' 
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"The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be.." - Douglas Adams
ambargh's easy agar
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Mephistophelian
Quasi Hob-Nobbery
Registered: 08/14/08
Posts: 2,527
Loc: Camp Crystal Lake
Last seen: 3 months, 1 day
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868790 - 07/08/10 05:28 PM (12 years, 10 months ago) |
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All petri dishes labeled as 'disposable' are Polystyrene.
Polystyrene differs from polypropylene & HDPE (High Density Poly Ethylene) is that it has a random crystal structure which loses its shape and form at high temperatures where the latter two plastics do not. While HDPE maximum working temperature is 121C (15psi) it can't take this over and over like Polypropylene.
In english, polystyrene is cheaply made for its simplicty and not made for re-use.
And ya, 8-year old thread. 
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jokefox
Top of the chain
Registered: 12/22/09
Posts: 6,231
Loc: never where I should be
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ya im going to give it a shot when im sober
i got some contamed plastic dishes
so there the best candidate
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ruckusman
Figment of my own imagination
Registered: 05/08/10
Posts: 190
Last seen: 2 years, 7 months
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12870429 - 07/08/10 10:55 PM (12 years, 10 months ago) |
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Old thread I know, but...
Check this link for autoclavable plastics
http://www.nalgenelabware.com/techdata/care/steril-autoclaving.asp
Mine were polystyrene
I tried a bleach bath (12 Hrs) followed by a Sodium precarbonate bath (12Hrs) -Laundry Oxidising stuff for nappies.
Then into a cardboard box which had been soaked with bleach and alcohol into a cracked oven, fan forced, on low heat to dry them out.
Seemed to be working until I decided to close the door for a bit to speed up the drying, forgot about them, and partially melted some that were close to the box - sides/top/bottom.
I haven't reused them yet, so need to repeat the process, with one change.
When I do I'm going to be using A4 protector sheets, which I've found can survive autoclaving with minimal shrinkage/damage, then into the cardboard box - oven.
The sheet protectors will be impulse sealed with a small section left open for evaporation, then sealed once dry.
It's a lot of work, but could get you out of a bind if you're waiting for new ones to arrive in the post.
I don't like wasting things either
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dcox420
Adrenaline Junkie
Registered: 08/06/08
Posts: 157
Loc: South East USA
Last seen: 9 years, 7 months
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Re: Steralizing Plastic Petri Dishes [Re: ruckusman]
#12871066 - 07/09/10 03:25 AM (12 years, 10 months ago) |
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Quote:
ruckusman said:
I tried a bleach bath (12 Hrs) followed by a Sodium precarbonate bath (12Hrs) -Laundry Oxidising stuff for nappies.
Then into a cardboard box which had been soaked with bleach and alcohol into a cracked oven, fan forced, on low heat to dry them out.
Well boss man I'm gonna take a shot in the dark here and say you have entirely toooooooooooo much free time and second the chemicals you used cost more than the set of disposable petri's.
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My Busa...Nothing better than hitting the highway at 3am with no traffic and kicking it up to 110-120.
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iluvfungi
Registered: 06/17/09
Posts: 1,488
Loc: Oakland, CA USA 
Last seen: 12 years, 21 days
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Re: Steralizing Plastic Petri Dishes [Re: dcox420]
#12871098 - 07/09/10 03:45 AM (12 years, 10 months ago) |
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Dood. They can be sterilized in the PC no problem. Just make sure to fill them with water before you put them in.
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ruckusman
Figment of my own imagination
Registered: 05/08/10
Posts: 190
Last seen: 2 years, 7 months
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Re: Steralizing Plastic Petri Dishes [Re: dcox420]
#12871260 - 07/09/10 06:15 AM (12 years, 10 months ago) |
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Quote:
dcox420 said:
Well boss man I'm gonna take a shot in the dark here and say you have entirely toooooooooooo much free time and second the chemicals you used cost more than the set of disposable petri's.
You're entirely right about having too much free time, but while they were in the bath I was having mine with my buddy
The chemicals cost maybe 30 cents
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hamloaf
Loaf of Fam.
Registered: 12/23/09
Posts: 20,192
Loc: Oklahoma. 
Last seen: 1 year, 21 days
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Re: Steralizing Plastic Petri Dishes [Re: ambargh]
#12871406 - 07/09/10 07:40 AM (12 years, 10 months ago) |
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Quote:
ambargh said:
Ummm... 8 yr old thread guys... Just sayin'
Ummmm.... 8 year old thread, yes.
Question the thread asks is still unanswered after 8 years.
This thread asks a relevant to the times question.
I personally have been pondering the same question my self.
(how to sterilize plastic petri dishes)
At least this isn't an eight year old thread asking,
"When do I dunk my cakes".
Then already been answered in the thread before bumpage.
When I get some empties.
I am gonna' try scrubbing them down good with 70% iso alcohol and a paper towel.
Then dry them in front of a flowhood.
HL
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Mephistophelian
Quasi Hob-Nobbery
Registered: 08/14/08
Posts: 2,527
Loc: Camp Crystal Lake
Last seen: 3 months, 1 day
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Re: Steralizing Plastic Petri Dishes [Re: hamloaf]
#12871430 - 07/09/10 07:55 AM (12 years, 10 months ago) |
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This all sounds like a great deal of trouble...when pyrex dishes have the least amount of work to re-sterilize and can slowly implemented over time. When there's an extra few bucks, buy 10. Once you have a handful, the problem is solved. That or just use baby jars/deli cups.
And to answer the question in a lame type of way, you can't "sterilize" the dishes because the temperature to reach sterilization level also melts the dish. The best one can do is to disinfect it and hope a hard-to-kill bacteria doesn't hang around during all this time. 8-year mystery solved 
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hamloaf
Loaf of Fam.
Registered: 12/23/09
Posts: 20,192
Loc: Oklahoma.
Last seen: 1 year, 21 days
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I am gonna have to disagree with you a little bit on your logic there, Mephistophelian.
The amount of trouble this may sound like to you.
May not sound like any amount of troble to the next person.
The amount of trouble sterilizing plastic petri dishes would be.
Is all in the eye of the beholder.
Personally. I have the time to wipe a few plastic petri dishes in alcohol.
Then place them in front of a flow hood to dry.
I wouldn't waste my time, personally, trying to PC plastic.
An alcohol scrub seems plausible to me.
So until research is done with alcohol to sterilize plastic petri dishes.
Gonna, have to say, no.
8 year old mystery not solved.
Besides that.
I am sure the "mystery" of sterilizing plastic petri dishes.
Spans longer than eight years and is confined to an internet chat board.
HL
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Mephistophelian
Quasi Hob-Nobbery
Registered: 08/14/08
Posts: 2,527
Loc: Camp Crystal Lake
Last seen: 3 months, 1 day
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Re: Steralizing Plastic Petri Dishes [Re: hamloaf]
#12871522 - 07/09/10 08:33 AM (12 years, 10 months ago) |
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The geek term I was refering to was the term "sterilization" which requires either an unholy bath of chemicals not usually confined to households, or using 121C at a minimum of 15 minutes. Unless you want to go beyond that to kill say prions, then you need 134C at beyond 60 minutes.
The point is...I was making a point that in terms of the word 'sterilization' which kills -everything- can't be done unless you have the proper range of chemical required with polystyrene (or UV death rays and so forth). Anything else is merely disinfectant and needs to be accepted that there is a small margin of contamination that can occur because of taking that route. Much like pasteurizing, it leaves room for something to come back eventually.
I bought a case of dishes for $100 more then a year ago, and I'm almost half-way through by this point. So for me, even with having 30+ dishes in my fridge at any one time...it would be a massive undertaking to clean them all up. If $$ or world supply was a significant issue...then I would consider trying to disinfect them. So I agree with you in that, to some...time is of no issue and they can spend quite a while disinfecting a handful of dishes at a time. Go to town guys.
But the geek point was, its not sterilization unless your using Lab Level UV/Radiation, Autoclave heat or Lab Level chemicals used as a autoclave replacement.
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hamloaf
Loaf of Fam.
Registered: 12/23/09
Posts: 20,192
Loc: Oklahoma.
Last seen: 1 year, 21 days
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Quote:
RogerRabbit said:
Quote:
iluvfungi said:
70% alcohol or 10% bleach solution does a pretty good job of killing anything. No need for a PC man.
That is incorrect. Alcohol and bleach are sanitizers, not sterilizers, and cultures slants need to be 100% sterile.
Culture slants need to be pressure cooked or autoclaved. You'll need to order glass tubes for long term storage.
RR
https://www.shroomery.org/forums/showflat.php/Number/12871500#12871500
Well this answers my question.
Don't worry.
Foot has been inserted into mouth. 
HL
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shubrick
Registered: 06/11/10
Posts: 145
Last seen: 2 years, 3 months
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Re: Steralizing Plastic Petri Dishes [Re: iluvfungi]
#12872653 - 07/09/10 01:10 PM (12 years, 10 months ago) |
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Quote:
iluvfungi said:
Dood. They can be sterilized in the PC no problem. Just make sure to fill them with water before you put them in.
I'm very skeptical of this.
If it is true that the plastic dishes will melt in a PC, then filling the dishes with water doesn't seem to make sense.
Water may provide physical support so that the Dishes don't buckle and warp, but I'd like to hear more about this.
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shubrick
Registered: 06/11/10
Posts: 145
Last seen: 2 years, 3 months
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Re: Steralizing Plastic Petri Dishes [Re: shubrick]
#12890761 - 07/13/10 12:48 AM (12 years, 10 months ago) |
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what about this: http://www.eurekalert.org/pub_releases/2006-02/asfm-vik021306.php
""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." "
Hat tip to RR; I saw this from him in another thread...
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fastfred
Old Hand
Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Steralizing Plastic Petri Dishes [Re: shubrick]
#12891377 - 07/13/10 06:09 AM (12 years, 10 months ago) |
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Your standard plastic dish will melt. A short cycle or less than 15psi might be good enough for your purposes, but that would take a bit of trial and error and it wouldn't be worth the increased contam rate, or even the mental worry.
I had some really big square dishes that I wanted to reuse. I found it effective to submerge them in 1:10 bleach solution for an hour or so. The problem is then drying them. It worked alright to smack them down in the flow hood. That got them dry enough.
Anyways, it's just not worth it to try reusing them. Buy glass ones if you want to reuse them.
-FF
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jokefox
Top of the chain
Registered: 12/22/09
Posts: 6,231
Loc: never where I should be
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Re: Steralizing Plastic Petri Dishes [Re: fastfred]
#12893746 - 07/13/10 04:40 PM (12 years, 10 months ago) |
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i tried to pc the normal petri dishes (disposable)
no luck
im going to try to pc both parts of the petri separately and see how that works
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Mephistophelian
Quasi Hob-Nobbery
Registered: 08/14/08
Posts: 2,527
Loc: Camp Crystal Lake
Last seen: 3 months, 1 day
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12893932 - 07/13/10 05:19 PM (12 years, 10 months ago) |
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Polystyrene Glass Temperature: 95C
Which translates to the temperature when the crystalline structure breaks down and it loses its rigidity and form.
0 PSI: 100C (212F)
5 PSI: 104C (220F)
10 PSI: 113C (235F)
15 PSI: 121C (250F)
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