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Shaking bacteria

  1. Mar 19, 2005 #1
    Should i cover my Erlenmeyer bottle with a folie when i shake my bacteria in the shaker? Should the covering be tight or loosen?

    Any suggestions?

    Thanks.
     
  2. jcsd
  3. Mar 19, 2005 #2
    Again depending on the bacteria, I'll assume its just E.coli which needs oxygen so then the anwer is tight enough to not let the folie shake off, causing possible contaminations. And loose enough to let oxygen in. Just wrap a small piece around the bottle neck and youll be fine
     
  4. Mar 19, 2005 #3

    Monique

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    You can use cotton plugs for that purpose, when you are sterilizing your erlenmeyer you should put a cotton plug into it, so that it will become sterile too.
     
  5. Mar 19, 2005 #4

    iansmith

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    You can also put aluminium foil on top of the erlenmeyer prior to sterilization. The idea is to cover the entry so contamination do not enter.

    However, if you are going to store the media for a certain time, you want to avoid evaporation. I find that screw cap flask are easier to work with you can have a better control over the entry of air and you can stop evaporation. If you don't have screw caps, the you need to use parafilm to stop the evaporation.
     
  6. Mar 19, 2005 #5
    Do you mean that i have to cover my bottle when i don't use it, under sterilizing and when i use it in shaking? How can i sterilize the inside of the bottle if i do cover it under sterilizing?

    Thanks.
     
  7. Mar 19, 2005 #6

    Moonbear

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    Aren't you keeping your glassware covered when autoclaving? You can't put a lid on tightly in the autoclave, or you'll just explode your flask, but a loose lid such as foil or cotton (cotton is really good because it will act like a filter while the flask is cooling; I've also used disposable surgical drapes folded over a few times and held in place with a rubber band) is essential. If you aren't covering your glassware in the autoclave, as soon as you remove it, it will quickly become non-sterile again as outside air (and bacteria, fungus, mold) enters it as it cools.
     
  8. Mar 20, 2005 #7

    Monique

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    You should always cover the erlenmeyer to keep it sterile. You sterilize with heat, so it does not matter if you cover it: just don't make a tight seal so that it will explode (as moonbear mentioned).

    The idea of using cotton while shaking your culture, is that it allows gas exchange, but it filters particles in air. Also it filters the aerosal with bacteria that might be created if you shake too vigorously.
     
  9. Mar 25, 2005 #8

    Ouabache

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    If you use a screw cap flask as iansmith suggests, I've always kept the caps partially screwed on, in the autoclave, so as to avoid exposions!! :surprised
    (I hate whenever that happens) ..

    Other variations, I've also autoclaved with Aluminum over cotton in Erlenmeyer flasks. If you are storing them before use, I've noticed they keep sterile longer than cotton alone.
     
  10. Mar 26, 2005 #9

    Ouabache

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    I forgot to mention, as soon as the screw-cap flasks are finished in the autoclave, I tighten the caps. Granted there is a chance of contamination as soon as unsterile air reaches them, but for practical purposes, this technique works well. :smile:
     
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