Does cooling water sterilise it?

[scilearner]

Hello everyone,

 

Let's say I want cool sterilised water. If I get water from my tap and put it in the fridge does that sterilize the water, or do I have to boil it first and then put it in fridge. I'm just asking this from a pratical point of view, from sterilisation I don't mean complete removal of microorganisms, I'm just asking if I boil and put it in fridge am I wasting my time. Thanks

[John Cuthber]

Just cooling the water won't kill anything.

In fact, some bugs will carry on multiplying slowly.

The best bet s to leave the water in the tap.

 

If you really need to get rid of micro-organisms then boiling the water is the simplest way.

 

What are you trying to achieve here?

[doG]

...am I wasting my time. Thanks

Yes

 

Oldest Living Thing Found in Ice

 

The oldest living thing has been discovered in the form of 600,000-year-old bacteria extracted from ice cores, scientists claim...

[Arete]

Tip: If you're not aiming to eliminate all of the potential life forms in water, you're sanitizing rather than sterilizing it

 

Putting water in the fridge will have a negligible effect on any microorganisms in it - as most of the kinds of organisms you'd wish to eliminate from it have thermal tolerances which well encompass what you can achieve in a home fridge/freezer. Heat (e.g. boiling) is much more effective. We have LN₂ on hand in our lab and -80C freezers, but we still use the autoclave to sterilize equipment.

 

Second what do you want it for? If you want to purify tap water for drinking, there's plenty of non-biological stuff you'd want to remove too, which heating will do nothing for such as heavy metals, nitrates, etc. Filtration is a much better way to make water more potable than boiling.

If you want it for experimentation, simply purchasing RO or distilled water will probably be far more cost effective than achieving the same level of purity with any method you could implement at home.

[scilearner]

Thank you both for your replies lol yes I needed it for drinking, I'm so stupid sometimes, this explains the mild stomach ache I had the other day.

[dmaiski]

if you want to sterilize something

its only a mater of how fast and how cold

 

-200C will kill almost all forms of life

if you get there fast enough (using even colder temperatures), a few seconds, shorter if you are trying to get rid of smaller substances

the mechanical stress will break down almost anything (including large molecules [proteins ect])

 

of course if your aiming for that level of sterilization:

1 silly, its easier to just vaporize everything (all you need is 2000-7000C), or nuke it (high concentration, beta and gamma radiation)

2 stupid, don’t make things that can survive normal sterilization procedures

3 crazy, paranoid delusions...

 

so in most cases the phrase "burn it with fire" is sufficient methodology to sterilize things

 

 

[John Cuthber]

if you want to sterilize something

its only a mater of how fast and how cold

 

-200C will kill almost all forms of life

if you get there fast enough (using even colder temperatures), a few seconds, shorter if you are trying to get rid of smaller substances

the mechanical stress will break down almost anything (including large molecules [proteins ect])

 

of course if your aiming for that level of sterilization:

1 silly, its easier to just vaporize everything (all you need is 2000-7000C), or nuke it (high concentration, beta and gamma radiation)

2 stupid, don’t make things that can survive normal sterilization procedures

3 crazy, paranoid delusions...

 

so in most cases the phrase "burn it with fire" is sufficient methodology to sterilize things

 

Wrong in almost every way.

Plenty of things survive being frozen. Bacteria and viruses are generally preserved by freezing, rather than killed.

Slow cooling does more damage than fast freezing.

200 degrees will kill a lot of things. 7000 is just a waste of time and energy. In particular, at 7000 degrees a lot of the water will dissociate so strictly speaking you won't have sterile water any more.

 

"burn it with fire" OK- it's water so how do you burn it?

[dmaiski]

you are right, 7000C is too high, you only need to hit 5000C to boil carbon

rapid freezing causes stress fractures in materials that cannot compress quickly thus breaking them down

slow freezing only damages biological materials because water crystallizes, most cells do not have free water in them, it is all chaperoned and controlled because free water can cause undesirable reactions anything that dose survive this will, at the verry least, be frozen solid and unable to react at 73K above zero while stored in a ice crystal

 

 

and you can burn water, after you split the individual molecules apart

 

i was going on the overkill assumption

"i have water that has [something horrible] in it and it will survive an autoclave/can not be autoclaved"

working along those lines i though of viable methods of sterilizing the water or at least preventing [something horrible] from doing something horrible

 

i understand that the question was only talking about drinking water, but an interesting thought experiment is too much fun to pass up and may be usefull at some point

 

 

 

 

but if your just looking to purify water the best way to do it is steam condensation, followed closely reverse osmosis, then by carbon filtration,

Edited September 13, 2012 by dmaiski

[John Cuthber]

"but if your just looking to purify water the best way to do it is steam condensation, followed closely reverse osmosis, then by carbon filtration,"

Or you could do it in the right order.

 

Microbiological specimens that are frozen for storage are placed in long thin packages called straws and plunged into liquid nitrogen.

That's so they get frozen as fast as possible and that is because its the way to get the greatest survival rates.

So this assertion "-200C will kill almost all forms of life

if you get there fast enough"

is still plain wrong.

 

"i have water that has [something horrible] in it and it will survive an autoclave/can not be autoclaved"

So it's really going to love 7000C

[dmaiski]

if it can survive 2100C past the boiling point of carbon you are S.O.L. and I would have to ask what exactly is it, and can i have some?

also if that is the case i would suggest either freezing it at 1K or nuking it with a 15MT tac-nuke

 

also:

"Lethal intracellular freezing can be avoided if cooling is slow enough to permit sufficient water to leave the cell during progressive freezing of the extracellular fluid. That rate differs between cells of differing size and water permeability: a typical cooling rate of about 1°C/minute is appropriate for many mammalian cells after treatment with cryoprotectants such as glycerol or dimethyl sulphoxide, but the rate is not a universal optimum."

 

thank you wikipedia: http://en.wikipedia.org/wiki/Cryopreservation#Risks

Edited September 16, 2012 by dmaiski

[John Cuthber]

When all is said and done, the answer to the original question is still no.

Your assertion that

" if you want to sterilize something its only a mater of how fast and how cold -200C will kill almost all forms of life"

is still wrong.

 

Freezing isn't a reliable way to sterilise things .