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 sparafucile
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Registered: 07/12/01
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 Steralizing Plastic Petri Dishes 
#620601 - 04/27/02 04:28 PM (22 years, 10 months ago) |
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Hi. I'm wondering, I've got some standard plastic petri dishes that I've already used. Therefore, I would like to steralize them in my pressure cooker. Is this possible? It doesn't seem like they would break, and other than keeping them from touching the sides while cooking, there shouldn't be any other problem, but I wanted to make sure. Does anyone know of any other good ways to steralize some dishes right before I drop some agar in them (lysol?)? Thanks for your time.
-recovering from contam 
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francisco
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 Re: Steralizing Plastic Petri Dishes [Re: sparafucile]
#620669 - 04/27/02 06:34 PM (22 years, 10 months ago) |
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They get deformed by the pressure/heat?i clean in a antimicrobial detergent and let dry in still air.Use 91% alcohol(walmart) to submerge the parts for a few seconds.Stack in your glove box and let dry.DANGER alcohol fumes will ignite in the present of any spart.even static charge so use caution when using.No smoking No open flames.
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Well...Maybe just a little.
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 shaggymane
PHARMER
Registered: 03/11/02
Posts: 514
Loc: great white north
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 Re: Steralizing Plastic Petri Dishes [Re: francisco]
#620670 - 04/27/02 06:39 PM (22 years, 10 months ago) |
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you can use Hydrogen peroxide .
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francisco
Richman Sporeman
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Re: Steralizing Plastic Petri Dishes [Re: shaggymane]
#620716 - 04/27/02 07:39 PM (22 years, 10 months ago) |
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i lose a few with h2o2 but it is safer
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Well...Maybe just a little.
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shubrick
 
Registered: 06/11/10
Posts: 145
Last seen: 4 years, 20 days
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Re: Steralizing Plastic Petri Dishes [Re: francisco]
#12868288 - 07/08/10 04:08 PM (14 years, 8 months ago) |
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Quote:
francisco said:
i lose a few with h2o2 but it is safer
wait, why would you lose a few using h2o2?
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jokefox
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Re: Steralizing Plastic Petri Dishes [Re: shubrick]
#12868306 - 07/08/10 04:12 PM (14 years, 8 months ago) |
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cant you do syringes in the pressure cooker if you wrap them in tinfoil
whats the purpose of the tin foil.. to act as a package?
i would Imagen the plastic is the same quality in the petris as the syringes
so in theory shouldent you be able to wrap tinfoil around the petri dishes and pressure cook
i have some zip ties that are only rated to 185F and they withstand the pressure cooker
just noticed.... 8 yr old thread
this is zombie shit now 
Edited by jokefox (07/08/10 04:13 PM)
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newbie_shroomer
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12868416 - 07/08/10 04:28 PM (14 years, 8 months ago) |
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Well if petri dishes deform then they may be a different type of plastic to the syringes. I have been told to use P5 plastic for pressure cooking but i have found that my p5 jars are quite thin and became deformed but the thicker ones where fine, so it may be a case f the plastics thickness.
The tinfoil would be used as a heat sink, so that your syringe is not touching the side of the PC directly causing it to melt? Well thats my guess anyway.
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jokefox
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so then in theory plastic petri dishes should hold up...
im going to try this later today , when im not to stoned to dump out contams
check back in a few hours for a result
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baron_samedi
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i was wondering the same thing i dont have the dishes yet but that is gonna be my first experiment plastic petris in an autoclave and i know for a fact that most lure lok syringes are autoclaveable without foil and they dont melt at all but i also putin autoclave bags so im not sure if that helps (thats how i do my syringes before i fill with sterile water). keep me posted
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fungus_tao
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Re: Steralizing Plastic Petri Dishes [Re: baron_samedi]
#12868530 - 07/08/10 04:45 PM (14 years, 8 months ago) |
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Are you guys talking about disposable plastic dishes? They melt.
Tao
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Follow the light
The Light is your guide.
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hamloaf
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868545 - 07/08/10 04:47 PM (14 years, 8 months ago) |
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I have been thinking, to sterilize plastic petri dishes.
How about a 70% alcohol bath.
Then dried in front of a flow hood.
I have yet to try this.
HL
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jokefox
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868555 - 07/08/10 04:49 PM (14 years, 8 months ago) |
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they melt?
at what pressure
im going to try 12 psi for 15 minutes
bath with 97% iso
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fungus_tao
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12868575 - 07/08/10 04:52 PM (14 years, 8 months ago) |
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Something like this would be better.
Tao
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Follow the light
The Light is your guide.
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M11
White Thumb
Registered: 06/14/09
Posts: 1,840
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12868590 - 07/08/10 04:54 PM (14 years, 8 months ago) |
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I think you should pressure cook them at 20 psi using 91% alcohol instead of water...
I would think PCing them at 12 psi for 20 minutes would be fine. I guess they could melt? I would wrap them in aluminum foil -not too tightly, but just enough.
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jokefox
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Re: Steralizing Plastic Petri Dishes [Re: M11]
#12868603 - 07/08/10 04:57 PM (14 years, 8 months ago) |
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have you ever added hot water to 97%iso
ya i did in a jar then put the disk over and shook it
and it exploded hot water all over my arms
i was shaking for 20 minutes after,, i needed a fat toke and a smoke to calm down
my arms were all burnt from the water to ... bad day
dont fuck with hot water and iso
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jokefox
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868605 - 07/08/10 04:57 PM (14 years, 8 months ago) |
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Quote:
fungus_tao said:
Something like this would be better.
Tao
i heard this doesent work
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Numinosum
President of Turd Town
Registered: 05/19/09
Posts: 1,175
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12868647 - 07/08/10 05:05 PM (14 years, 8 months ago) |
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Double post
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...within my memory is the knowledge of hyper-light drive ships and how to build them.
Doc_T's Efficiency Challenge
Edited by Numinosum (07/08/10 05:06 PM)
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Numinosum
President of Turd Town
Registered: 05/19/09
Posts: 1,175
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Re: Steralizing Plastic Petri Dishes [Re: Numinosum]
#12868652 - 07/08/10 05:05 PM (14 years, 8 months ago) |
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Quote:
Numinosum said:
Quote:
jokefox said:
Quote:
fungus_tao said:
Something like this would be better.
Tao
i heard this doesent work
My wife bought one of those, I laughed. The thing costs like $40 dollars. Germicidal lamps
used in labs cost hundreds yes? Anyway, when I read the instructions it tells you how long to
keep the light over the surface, I forget how long now but I do remember it was a little
ridiculous.
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...within my memory is the knowledge of hyper-light drive ships and how to build them.
Doc_T's Efficiency Challenge
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fungus_tao
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12868690 - 07/08/10 05:09 PM (14 years, 8 months ago) |
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UVC is the same thing used in the bacti cinerator.
From wikipedia:
Quote:
Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities.
Tao
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Follow the light
The Light is your guide.
Edited by fungus_tao (07/08/10 05:14 PM)
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fungus_tao
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868705 - 07/08/10 05:13 PM (14 years, 8 months ago) |
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Quote:
Anyway, when I read the instructions it tells you how long to
keep the light over the surface, I forget how long now but I do remember it was a little
ridiculous.
I can see why the home use ones would be numbed down a bit so people don't give themselves skin cancer and sue. Maybe these types aren't as effective 
Jokefox, are you PC'ing plastic dishes?
Tao
--------------------
Follow the light
The Light is your guide.
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Tolerated
Master Contaminant Grower
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868773 - 07/08/10 05:25 PM (14 years, 8 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 (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: fungus_tao]
#12868790 - 07/08/10 05:28 PM (14 years, 8 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
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Posts: 6,231
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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
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12870429 - 07/08/10 10:55 PM (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: ruckusman]
#12871066 - 07/09/10 03:25 AM (14 years, 8 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.
--------------------
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
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Re: Steralizing Plastic Petri Dishes [Re: dcox420]
#12871098 - 07/09/10 03:45 AM (14 years, 8 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
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Posts: 190
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Re: Steralizing Plastic Petri Dishes [Re: dcox420]
#12871260 - 07/09/10 06:15 AM (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: ambargh]
#12871406 - 07/09/10 07:40 AM (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: hamloaf]
#12871430 - 07/09/10 07:55 AM (14 years, 8 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
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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
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Re: Steralizing Plastic Petri Dishes [Re: hamloaf]
#12871522 - 07/09/10 08:33 AM (14 years, 8 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
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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: 4 years, 20 days
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Re: Steralizing Plastic Petri Dishes [Re: iluvfungi]
#12872653 - 07/09/10 01:10 PM (14 years, 8 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: 4 years, 20 days
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Re: Steralizing Plastic Petri Dishes [Re: shubrick]
#12890761 - 07/13/10 12:48 AM (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: shubrick]
#12891377 - 07/13/10 06:09 AM (14 years, 8 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 (14 years, 8 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
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Re: Steralizing Plastic Petri Dishes [Re: jokefox]
#12893932 - 07/13/10 05:19 PM (14 years, 8 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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