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I want to stock up on autoclaved disposables, such as Eppendorf tubes, pasteur pipettes etc., and some buffers.

If I don't open the container after autoclaving, how long can I store autoclaved materials and consider them still sterile? Does it make a difference if the material is dry or if it is a liquid?

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This is a non-answer, but may be worth checking out for other reasons: ohp.nasa.gov/policies/pdf/WFF_Autoclave_Recommendations.pdf –  dd3 Mar 7 '13 at 21:00
    
This page for surgical instruments says it's 2 months, or 6-12 months: research.drexel.edu/forms/compliance/iacuc/pol_autoclaving.pdf. I imagine that disposables might be less... –  dd3 Mar 7 '13 at 21:02
    
@dd3: why would it be less? –  nico Mar 29 '13 at 16:38
    
@nico: To be honest, I was mostly thinking of degradation of plastics. That's probably not the issue here, though. –  dd3 Mar 29 '13 at 17:03

2 Answers 2

up vote 3 down vote accepted

Not really an answer I know, but too long for the comments...

This is still too broad a question. a well sealed, sterile plastic usually has a use by date, but can probably be used more than a year after you receive it. But these cases are not usually the issue.

Its sterile medium and chemicals, each of which needs to have their own due date. LB can be used months after autoclaving, but antibiotics break down chemically in weeks (ampicillin 1000x stocks lose their potency in a month). Even in the refrigerator Agar plates show colonies after a couple of months and dry out quickly.

So more details would be necessary and the case by case policy is the rule.

added in response to comments

Its really a matter of how well they are sealed. An autoclaved bottle will stay sterile forever, until something gets into the bottle - it depends on how well you have sealed things up and the storage conditions. For stuff sterilized in lab I would tend to use it within a couple of months. For eppendorfs we'd tend to sterilize a few hundred in a beaker and not worry about them...

Our experiments were working with purified protein were only medium sensitive to bio-contamination; they would be done in a few hours and then sterile filtered again. If you were purifying RNA for instance you would be much more paranoid I'm sure.

If you start to see contamination I would lower the use date and or improve your protocol.

Plastics that come sterilized and sealed by the manufacturer in 3-5 mil plastic bags have really long use by dates and I've used them for up to a year after we received them.

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Thanks, I was asking specifically for plastics and buffers, such as PBS. No medium or antibiotics. –  Drosophila Mar 29 '13 at 14:58
    
I wouldn't use sterilized buffers more than a week after I made them - sterile filtering is easy to do just before you use them. but that's me. –  shigeta Mar 30 '13 at 4:02
    
Great, so from what I gather: sealed autoclaved plastics can be used even after a year of storage. It is safe to presume buffers are good for a week. That pretty much answers my question. I think it outlined clearly in the answer for future reference. –  Drosophila Mar 30 '13 at 4:29
    
i see - i've added to the response. this is getting into subjective territory, but I put in some more detail there... there are bound to be those who disagree :) if you are starting to work with animal cells or bacteria it will really vary. This answer might be enough to get you started... –  shigeta Mar 30 '13 at 14:36
    
can you even safely autoclave ampicillin? I would have thought it would degrade in solution at that temperature. –  user137 2 hours ago

If you work in a lab, there must be a SOP(Standard Operating Procedure) and you can (You should...) follow that. Each lab will have different standard so providing a single definitive answer here may not be beneficial.

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Thanks, but I posted this because it's up to me to establish the SOP in this case :) –  Drosophila Feb 27 '13 at 2:28
    
I expect there to be different established practices. I just need a ballpark of the amount of time I can store autoclaved products - that should be an objective measure. –  Drosophila Feb 27 '13 at 2:35
    
The question is quite clear: how long autoclaved plasticware stays sterile? Sterility does not in any way depend on SOP. Either something is sterile or it is not. –  nico Mar 29 '13 at 16:40

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