WHen you autoclave - Use aluminium foil (Apr/16/2009 )
josse on Apr 17 2009, 05:17 PM said:
when we use the autoclave we have the pipettips in a plastic box and around the lid of the box (the gap you see) we put some indicator tape (completely around the box)
Now reading your posts here I wonder whether the tips are sterile like this, because they are in a box and sealed.
And what with other objects like a little jar or tweezers. We wrap aluminum foil around it, put in the autoclave and then we take it out and put it in the cabinet and we assume it stays sterile. But is this even ok?
and another question:
Why?
and when the autoclaving is done, you simply let the products in the autoclave to dry or?
I mean: when I finished autoclaving the products are always wet but we take them out and put them inside the cabinet.
(keep in mind we do use the simplest autoclave possible: a stovetop autoclave)
Often we follow a procedure because it is the "way things have always been done in this lab". More often than not the procedure will work fine. Most of the time.... But why risk a cloning experiment or a primary cell culture because of the poor preparation of sterile starting materials? We have enough to worry about with our experiments than being concerned about something being "sterile enough".
A bit of equipment being "sterile enough" is like a woman being "almost pregnant"! It is or it is not.
As mentioned above, if you hamper steam penetration (eg by sealing tip boxes with autoclave tape), you risk inadequate sterilization. Always wrap dry goods in steam-permeable packs if they are to be autoclaved. Special autoclave bags are best, but filter paper is also adequate.
I always use a machine that pulls a high vacuum after sterilization in order to dry the goods. If your stovetop autoclave cannot dry well it is probably a good idea to place the sterilised material on a ethanol-cleaned LAF bench until dry.
By the way, I found out how to sterilize items correctly AFTER losing $ 13, 000 (yes three zeros) worth of immunomagnetic beads because of an inadequately autoclaved bottle. Once done, never forgotten.
I see, thanks klinmed.
I do know that the boxes we use always seem to be wet inside. Maybe its some sort of plastic that lets steam pass ? Dont you think that the people that make those pipetboxes build them so that steam can penetrate?
however still another question: why does it need to be dry when storing it? does a wet object attrackt more micro-organisms?
josse on Apr 18 2009, 05:54 AM said:
I do know that the boxes we use always seem to be wet inside. Maybe its some sort of plastic that lets steam pass ? Dont you think that the people that make those pipetboxes build them so that steam can penetrate?
however still another question: why does it need to be dry when storing it? does a wet object attrackt more micro-organisms?
I think its because wet area, microorganisms can grow on it so it will not be sterile anymore. There are microorganism in the air also so if its wet then it will be contaminated very fast.
I would like to add some comments :
first sterility is not black or white. It's just a way to reduce the risk of a contamination to the lowest point, however the probability of a contamination will never be zero.
Second, the tip boxes are not so well closed that they do not let the steam enter. So, your tips are sterilised. If you open the autoclave to early, there will be water inside the box, it's the condensation of the steam. We let all the material dry in a Pasteur oven, to be sure there will be no water inside the boxes.
guys, i want to ask additional question, my colleague used autoclave machine to sterile his cloning plate containing media for bacterial culture before he discard it.
any suggestion or advice to avoid leaking, or negative effect? since last time, i asked him is it safe to autoclave media containing plate becos i afraid it will leak and clog the autoclave drainage system.
tq
fitriyusof on May 9 2009, 02:12 PM said:
any suggestion or advice to avoid leaking, or negative effect? since last time, i asked him is it safe to autoclave media containing plate becos i afraid it will leak and clog the autoclave drainage system.
tq
There are special (and expensive) autoclave bags available for this.
hobglobin on May 9 2009, 09:43 AM said:
fitriyusof on May 9 2009, 02:12 PM said:
any suggestion or advice to avoid leaking, or negative effect? since last time, i asked him is it safe to autoclave media containing plate becos i afraid it will leak and clog the autoclave drainage system.
tq
There are special (and expensive) autoclave bags available for this.
yes we do,but it still leaving the smell of the media.hooe to overcome this?tq