Autoclave/pressure Cooker.... Anyother Ways?

[dj1984]

Just got some test tubes and some petri dishes and keen too get slanting.

The only thing i done have is a pressure cooker or autoclave.

Anyone got a different way of doing it that works??

Cheers
DJ

 

[Andyd]

I do mine in a baby bottle sterilizer I picked up on ebay for $10. There's plenty around...

Andy

 

[Ducatiboy stu]

Boil them or use a hot oven for 30min

 

[b_thomas]

170c in an oven for 30mins will sterilise

(put the glass in a cold oven - though I don't think it applies to scientific glass)

 

[RdeVjun]

Mumsie would never let me forget it if I lob around asking to borrow her ancient pressure cooker, I'll never hear the end of the ribbing I'd get if I did. :lol:

So, stockpot, an inch or two of water in it and a baking/ cooling rack to fit, then on the stove. More of a simple steamer, in fact a steamer will do fine, just let either run for an hour or more and most of the troublesome bugs are nuked. Various theories abound about the required time, I'm just being conservative.
I bung in starters, caps, media, slants, skewers etc, just about everything needed to propagate that there's room for, everything else on the bench gets a few pure alcy squirts.

That reminds me, I've got a pack of 1768 to slant before it snuffs it completely.

 

[Sammus]

Id definitely fork out for a pressure cooker for this kinda thing, might set you back 100, but when your culturing yeast from single cells, contamination is a big issue, and sterility is an absolute must. Steaming and whatnot will sanitize it to an extent, but there is a reason surgical equipment and tattoo and piercing needles etc arent just boiled in water - its not sufficient for sterilisation.

 

[Bribie G]

Edit:
deleted post, you don't have ALDI in SA, yet.

 

[raven19]

I use a large saucepan with an inch of water.

Inside place a pyrex container, place your items for sterilising in this.



Then simmer with the lid on for 15 minutes.

The steam will sterilise things nicely.

I tend to make blank slants up and put the lids on them loosely - so when it cools back down after 15 minutes, you can just screw them up tight - place in fridge, ready for slanting whenever you need them.

 

[chris.taylor.98]

You can increase the effectiveness of the pot method by putting a weight on the lid ( there by increasing the pressure inside and the temperature ). I do this for about 45 mins.

Sterilisation is a temperature and time balance. For autoclave (using water vapour) it is supposed to be 123C for 15mins. If you go lower temp you need to increase the time.

Doing it at twice at boiling temp was the original method used ( ie heat to boiling, hold for a period, let cool to ambient, heat back to boiling and hold again ).

Anyway with slants you are soon going to know if they got contaminated or not.

Just find a method that works for you and your setup.

 

[raven19]

Fair call CT - I am pretty sure I use your method posted many moons ago!

I tend to leave a blank slant out on the bench at room temp as a 'quality control' measure. If it goes bad then I redo the lot.

 

[Fourstar]

Fair call CT - I am pretty sure I use your method posted many moons ago!

I tend to leave a blank slant out on the bench at room temp as a 'quality control' measure. If it goes bad then I redo the lot.

As do I. Awesome method and it works!

 

[TidalPete]

You can increase the effectiveness of the pot method by putting a weight on the lid ( there by increasing the pressure inside and the temperature ). I do this for about 45 mins.

Sterilisation is a temperature and time balance. For autoclave (using water vapour) it is supposed to be 123C for 15mins. If you go lower temp you need to increase the time.

Doing it at twice at boiling temp was the original method used ( ie heat to boiling, hold for a period, let cool to ambient, heat back to boiling and hold again ).

Anyway with slants you are soon going to know if they got contaminated or not.

Just find a method that works for you and your setup.

I remember that post too.
Used to just boil the crappers out of everything for 40 minutes & which worked ok but stopped after I got a cheap pressure cooker on Ebay & that was that.

TP

 

[dj1984]

Ok, so i gave the pot with water trick a go and it has worked so far (did it last night).

Now just have too get a loop and im slanting.

Cheers for the help guys.

DJ

 

[Nick JD]

The pot of water steam bath also works well for propagating certain other interesting fungal mycelium cultures in starch solutions.

 

[raven19]

For the loop - I used to use a straightened paperclip, but recently got some mig welding wire - nice and thin, easy to bend, and gets red hot quicker under a flame.

Just hold it in a wooden peg and you are away! :icon_cheers:

Edit - grammar

 

[Georgedgerton]

So where is the best place to purchase flat bottom test tubes?

 

[Effect]

I use a large saucepan with an inch of water.

Inside place a pyrex container, place your items for sterilising in this.

View attachment 31988

Then simmer with the lid on for 15 minutes.

The steam will sterilise things nicely.

I tend to make blank slants up and put the lids on them loosely - so when it cools back down after 15 minutes, you can just screw them up tight - place in fridge, ready for slanting whenever you need them.

exactly what I do...and even use the same pyrex jug.

Cheers
Phil

 

[raven19]

So where is the best place to purchase flat bottom test tubes?

Any laboratory supply stores.

Google should provide some in your local area or at least in Aus.

 

[Andyd]

Even if you find a flat bottomed test tube (which isn't impossible, but not likely I think), it's never going to stand up on that bottom - it's just too unstable.

I get my gear from Livingstone International, whoc are pretty good to deal with by mail order. I use plastic tubes for slants which I sterilize in the aforementioned bottle steamer.

Andy