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Hey All,

I know it should probably be okay, but I want to sterilize some rubber stoppers that will be needed in a prac in the near future. I am going to sterilize them in the pressure cooker at 121 degrees for the usual 15-20min time frame. I just wanted to double check and see if they will be safe and not melt in the cooker.

Anyone ever sterilize rubber stoppers before?

Cheers,

Lazza

I haven't done this before, but my question is, how will you keep them sterile after they're 'cooked'? I have sterilised cotton tips in brown paper bags before but I don't know how sterile they really are... What is the prac that they need to be sterilised for? Maybe just try one stopper to start with just to be sure they won't melt... Good luck!

They should not melt, but what about using 70%alcohol and sit the stoppers in it, just before use.
Lada

They will be used to model Pasteur's Experiments with the broth and the different shaped glass tubing. The experiment didn't work last time so I plan on sterilizing everything including rubber stoppers and glass tubing before they are used again. The standard washing of the tubing and stoppers obviously isn't enough. There might be microbes still inside the curviture of the glassware that cannot be reached and I figure I might as well get the rubber stoppers cleaned as well. Once sterilized and allowed to cool in the pressure cooker I will store in sterile bags until ready for use for the next time. Or better yet, sterilize them in the autoclave bags and keep them in there until needed for the next prac. I figure it's worth a try and I am sure this way the results will be heaps better then what they were the last time around.

lada wrote:They should not melt, but what about using 70%alcohol and sit the stoppers in it, just before use.
Lada

That's another good option! Thanks Lada

Everything in that prac should be sterilised during the process of setting it up (they boil it for 20min or something). Good luck though - let us know if it works!

I do not sterilise anything for this prac, as students boil broth.
We have no problems with this practical,we dont always get a good growth in the ones, we should, but we never have anything in the others.
Good luck,
Lada

We do the same as Lada. And get similar results.

Use Milton (dilute solution) to soak the stopper and tubing, overnight before using. No need to rinse. Check your broth, I use boiled chicken broth. takes time for reaction (usually 2-3 weeks) to be visible, when weather is too cold, I put them (set-up) in and out incubator to have a warmer temperature to enhance growth.

Yeah... our students boil the broth as well, but for some reason there was heaps of microbial growth in the flasks where there shouldn't have been any growth (curved glass tubing) which is why I have had to even consider sterilizing everything before the prac. I will be sure to post the results of the outcome. Stay tuned and thanks for all the great advice and support....

I soak everything in a bucket of bleach for the night before this prac. I make up my own broth by boiling up chicken wings or drumsticks and the students then boil it in the flasks before they seal the top or do what they need to do. I have had no problem with anything growing in the sealed flasks. I use a coil of rubber tubing for one part of this, and also those double sealers that you can get for brewing beer.. both work reallywell.

Just a thought. You know they have to boil it with the stoppers and tubing in place (whole set up)?
Lada