On Sat, 6 May 2006, David P wrote:

On 06 May 2006, Dave
wrote:

On Sat, 06 May 2006 00:34:13 +0100, The Natural Philosopher
wrote:

|Raising the water to 60 C kills about 95% of the bugs in seconds.

That temperature is actually *82* deg C to kill food poisoning bugs
Some food poisoning bugs breed nicely below 64 deg C

I think amino-acids/proteins get denatured (and becoma deformed beyond
use) at about 62 degrees.

Depends on the protein - there's quite a variation in denaturation
temperature, and it depends on the chemical environment etc. 60-odd
degrees is in the right area, though.

I thought that was the basis for saying that food (eggs, meat, etc) must
be cooked over approx 62 C.

That's because that's the sort of temperature where collagen denatures,
becoming gelatin, which is how cooking softens meat. I believe collagens
from different kinds of animals have different conversion temperatures - i
ISTR 58 C for fish and 65 C for mammal meat.

tom

--
Everything that has transpired has done so according to my design.

On Sat, 6 May 2006 13:25:22 +0100, Tom Anderson
wrote:

|On Sat, 6 May 2006, David P wrote:
|
| On 06 May 2006, Dave
| wrote:
|
| On Sat, 06 May 2006 00:34:13 +0100, The Natural Philosopher
| wrote:
|
| |Raising the water to 60 C kills about 95% of the bugs in seconds.
|
| That temperature is actually *82* deg C to kill food poisoning bugs
| Some food poisoning bugs breed nicely below 64 deg C
|
| I think amino-acids/proteins get denatured (and becoma deformed beyond
| use) at about 62 degrees.
|
|Depends on the protein - there's quite a variation in denaturation
|temperature, and it depends on the chemical environment etc. 60-odd
|degrees is in the right area, though.
|
| I thought that was the basis for saying that food (eggs, meat, etc) must
| be cooked over approx 62 C.
|
|That's because that's the sort of temperature where collagen denatures,
|becoming gelatin, which is how cooking softens meat. I believe collagens
|from different kinds of animals have different conversion temperatures - i
|ISTR 58 C for fish and 65 C for mammal meat.

I am not disputing your protein denaturing figures, it is just that
bacteria are not just protein, but a lot tougher. Some will withstand
greater than 100 deg C and even breed at that temp.

http://textbookofbacteriology.net/nutgro.html
Table 10c. Hyperthermophilic Archaea.

Temperature for growth(degrees C)
Genus Minimum Optimum Maximum Optimum pH
Sulfolobus 55 75-85 87 2-3
Desulfurococcus 60 85 93 6
Methanothermus 60 83 88 6-7
Pyrodictium 82 105 113 6
Methanopyrus 85 100 110 7


Figure 8. Sulfolobus acidocaldarius is an extreme thermophile and an
acidophile found in geothermally-heated acid springs, mud pots and surface
soils with temperatures from 60 to 95 degrees C, and a pH of 1 to 5. Left:
Electron micrograph of a thin section (85,000X). Under the electron
microscope the organism appears as irregular spheres which are often lobed.
Right: Fluorescent photomicrograph of cells attached to a sulfur crystal.
Fimbrial-like appendages have been observed on the cells attached to solid
surfaces such as sulfur crystals.T.D. Brock. Life at High Temperatures.


--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

David P wrote:
I don't know what iron barrel is but some of the feed pipes from the
rising main into the roofspace look as if they might be made of steel.

The building is about 40 years old.

Iron pipes were used extensively. I'd be surprised if they were
used only 40 years ago, though, because plastic/copper was normal.

On Sat, 06 May 2006 13:14:45 +0100, Andy Hall wrote:

|On Sat, 06 May 2006 13:06:29 +0100, Dave Fawthrop
wrote:
|
|On Sat, 06 May 2006 12:30:00 +0100, Andy Hall wrote:

|
|
||The only Life without risk is death.
||
||Of course, so why spoil it with foul tasting tap water?
|
|Our tap water straight off the Yorkshire peat moors tastes fine.
|
|I'm sure that that's true. Do they have to add calcium salts to
|buffer it back up to a reasonably pH neutral level?

They used to stop the lead pipes dissolving, not sure about now.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

On Sat, 6 May 2006, Dave Fawthrop wrote:

On Sat, 6 May 2006 13:25:22 +0100, Tom Anderson
wrote:

|On Sat, 6 May 2006, David P wrote:
|
| On 06 May 2006, Dave
| wrote:
|
| On Sat, 06 May 2006 00:34:13 +0100, The Natural Philosopher
| wrote:
|
| |Raising the water to 60 C kills about 95% of the bugs in seconds.
|
| That temperature is actually *82* deg C to kill food poisoning bugs
| Some food poisoning bugs breed nicely below 64 deg C
|
| I think amino-acids/proteins get denatured (and becoma deformed beyond
| use) at about 62 degrees.
|
|Depends on the protein - there's quite a variation in denaturation
|temperature, and it depends on the chemical environment etc. 60-odd
|degrees is in the right area, though.
|
| I thought that was the basis for saying that food (eggs, meat, etc) must
| be cooked over approx 62 C.
|
|That's because that's the sort of temperature where collagen denatures,
|becoming gelatin, which is how cooking softens meat. I believe collagens
|from different kinds of animals have different conversion temperatures - i
|ISTR 58 C for fish and 65 C for mammal meat.

I am not disputing your protein denaturing figures, it is just that
bacteria are not just protein, but a lot tougher. Some will withstand
greater than 100 deg C and even breed at that temp.

Oh, absolutely. I wasn't disputing that at all - just commenting on the
denaturation of protein and its relation to cooking (trying to hold up the
uk.food+drink.misc end here!). As you say, there are certainly
thermophilic bacteria that will survive elevated temperatures, even above
100 C. None are pathogenic, AFAIK - indeed, body temperature is probably
too low for them (as for the examples you gave).

What's more of a concern is bacterial spores; i'm hazy on the details, but
i believe there are spore forms of some pathogenic bacteria that will
survive 100 C temperatures; that's why medical autoclaves go to 100 C -
15 mins at 121 C is the traditional gold standard for autoclaves, although
the one in my old lab went up to 140 C (and it looked like R2D2 - bonus!).

Okay, have looked it up - pathogenic spore-forming bacteria (and the
diseases they case) include _Clostridium tetani_ (tetanus), _Bacillus
anthracis_ (anthrax), _Clostridium perfringens_ and _Bacillus cereus_
(food poisoining), and _Clostridium botulinum_ (botulism).

So, if you've got any of those in your hot tank, well, you're buggered
either way, basically.

tom

--
Know who said that? ****ing Terrorvision, that's who. -- D

Tom Anderson typed

What's more of a concern is bacterial spores; i'm hazy on the details, but
i believe there are spore forms of some pathogenic bacteria that will
survive 100 C temperatures; that's why medical autoclaves go to 100 C -
15 mins at 121 C is the traditional gold standard for autoclaves, although
the one in my old lab went up to 140 C (and it looked like R2D2 - bonus!).

Okay, have looked it up - pathogenic spore-forming bacteria (and the
diseases they case) include _Clostridium tetani_ (tetanus), _Bacillus
anthracis_ (anthrax), _Clostridium perfringens_ and _Bacillus cereus_
(food poisoining), and _Clostridium botulinum_ (botulism).

So, if you've got any of those in your hot tank, well, you're buggered
either way, basically.

I doubt it; the clostridia are anaerobes and don't tolerate air very
well. Down in the soil, they are almost universal.

You probably have them in small, manageable numbers in your healthy
intestines anyway. (Please wash hands after using the WC. It is more
important to physically remove muck than to apply antiseptics in normal
situations.)

--
Helen D. Vecht:
Edgware.

Dave Fawthrop wrote:
On Sat, 06 May 2006 12:07:55 +0100, The Natural Philosopher wrote:

|It is an observed fact that the population of this country are not all
|dying of cholera, staphylcoccus, streptococcus and E colii, and didn';t
|die before we had mains water, as long as they boiled the kettle or
|added a bit of alcohol for their 'small beer'

Not all but a significant number die of food poisoning, Remember the
Scottish case.

Not from drinking contaminated water though.

Last weeks Tesco's pork pie is far more dangerous.

Andy Hall wrote:
On Sat, 06 May 2006 12:17:16 +0100, The Natural Philosopher
something rather than a dead sheep wedged in a stone wall?

I don't have knee jerk reactions. Only carefully considered ones.



Somehow I think you have fallen for a false sense of freedom.

I suggest you actually carry out tests, or find someone else to, on
bottled water.

Dave Fawthrop wrote:
On Sat, 6 May 2006 13:25:22 +0100, Tom Anderson
wrote:

|On Sat, 6 May 2006, David P wrote:
|
| On 06 May 2006, Dave
| wrote:
|
| On Sat, 06 May 2006 00:34:13 +0100, The Natural Philosopher
| wrote:
|
| |Raising the water to 60 C kills about 95% of the bugs in seconds.
|
| That temperature is actually *82* deg C to kill food poisoning bugs
| Some food poisoning bugs breed nicely below 64 deg C
|
| I think amino-acids/proteins get denatured (and becoma deformed beyond
| use) at about 62 degrees.
|
|Depends on the protein - there's quite a variation in denaturation
|temperature, and it depends on the chemical environment etc. 60-odd
|degrees is in the right area, though.
|
| I thought that was the basis for saying that food (eggs, meat, etc) must
| be cooked over approx 62 C.
|
|That's because that's the sort of temperature where collagen denatures,
|becoming gelatin, which is how cooking softens meat. I believe collagens
|from different kinds of animals have different conversion temperatures - i
|ISTR 58 C for fish and 65 C for mammal meat.

I am not disputing your protein denaturing figures, it is just that
bacteria are not just protein, but a lot tougher. Some will withstand
greater than 100 deg C and even breed at that temp.

http://textbookofbacteriology.net/nutgro.html
Table 10c. Hyperthermophilic Archaea.
Temperature for growth(degrees C)
Genus Minimum Optimum Maximum Optimum pH
Sulfolobus 55 75-85 87 2-3
Desulfurococcus 60 85 93 6
Methanothermus 60 83 88 6-7
Pyrodictium 82 105 113 6
Methanopyrus 85 100 110 7


Figure 8. Sulfolobus acidocaldarius is an extreme thermophile and an
acidophile found in geothermally-heated acid springs, mud pots and surface
soils with temperatures from 60 to 95 degrees C, and a pH of 1 to 5. Left:
Electron micrograph of a thin section (85,000X). Under the electron
microscope the organism appears as irregular spheres which are often lobed.
Right: Fluorescent photomicrograph of cells attached to a sulfur crystal.
Fimbrial-like appendages have been observed on the cells attached to solid
surfaces such as sulfur crystals.T.D. Brock. Life at High Temperatures.



Fortunately for us, species adapted for 100C do not do well inside a
stomach at 38C...

In short, most if not all bacteria that are happy to live inside us, are
not happy to live at the temperatures at which food is cooked (about
50-100C depending) Nor at temperatures around freezing or les. Like us,
they die at those sorts of temperatures, which is why we freeze food,
and we cook it.

Now of course the stupid little pedants will jump in and tell you that
this doesn't kill them ALL. but so what? the world is full of bacteria,
and thats why we have immune systems.

Nothing is safe, but water at 60C plus is a lot safer than eating a two
week old pork pie.

On Sat, 06 May 2006 21:25:52 +0100, The Natural Philosopher
wrote:

Andy Hall wrote:
On Sat, 06 May 2006 12:17:16 +0100, The Natural Philosopher
something rather than a dead sheep wedged in a stone wall?

I don't have knee jerk reactions. Only carefully considered ones.



Somehow I think you have fallen for a false sense of freedom.

I suggest you actually carry out tests, or find someone else to, on
bottled water.





No need.


--

..andy

On Sat, 06 May 2006 13:37:02 +0200 someone who may be Mxsmanic
wrote this:-

Where do you think these very high levels of iron will come from?

Iron in surfaces that are in contact with the water.

Iron surfaces in contact with water that will be drunk from the hot
tap. Hmmmm. Can't think of that many in UK plumbing, other then any
old-fashioned direct hot water systems (including the ones with the
old square hot water tanks). I imagine there are a few of these left
in the UK, but not many.

If the water in my water heater stands for a long period, it looks a
bit rusty the next time I take water from it,

And what sort of heater is that?



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Sat, 06 May 2006 13:40:17 +0200 someone who may be Mxsmanic
wrote this:-

Hot water sits for long periods in a very old tank under pressure.

What pressurises it?

If it is under pressure in a very old iron tank then the tank could
well fail at any time and, as others have said, replacement should
be a priority.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

David P writes:
What about chemicals/metals/minerals getting into the water from
parts of the hot water system?

It probably depends a lot of the water's pH and natural mineral and
gas content, but around here it is recommended that when preparing
beverages we use water from the cold tap. My understanding is that
copper dissolves better in hot water, so water that has been standing
in the hot water tank emerges with a higher copper content than water
that has been standing for equal time in cold copper pipes.

To avoid unwanted copper intake, fill your electric jug from the cold
water tap even though it will take a minute more to bring to the boil.
--
John Savage (my news address is not valid for email)

In article ,
John Savage wrote:
It probably depends a lot of the water's pH and natural mineral and
gas content, but around here it is recommended that when preparing
beverages we use water from the cold tap. My understanding is that
copper dissolves better in hot water, so water that has been standing
in the hot water tank emerges with a higher copper content than water
that has been standing for equal time in cold copper pipes.

To avoid unwanted copper intake, fill your electric jug from the cold
water tap even though it will take a minute more to bring to the boil.

And the extra time taken dissolves nasty chemicals from the kettle body?

First I've heard of copper dissolving in hot water. How long does it take
for the pipes to disappear?

--
*Life is hard; then you nap

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" writes:
In article ,
John Savage wrote:
It probably depends a lot of the water's pH and natural mineral and
gas content, but around here it is recommended that when preparing
beverages we use water from the cold tap. My understanding is that
copper dissolves better in hot water, so water that has been standing
in the hot water tank emerges with a higher copper content than water
that has been standing for equal time in cold copper pipes.

To avoid unwanted copper intake, fill your electric jug from the cold
water tap even though it will take a minute more to bring to the boil.

First I've heard of copper dissolving in hot water. How long does it take
for the pipes to disappear?

No one knows; we throw out the HWS as soon as one tiny spot in the copper
coils corrodes all the way through. Wasteful innit?

The time this takes varies a lot with what's in the water you feed the
system. 30 years for rural rainwater, 8 years for caustic acid rain. But
you'll notice that cold water pipes of similar gauge are set to last for
centuries.

Copper dissolves in cold water too, but more will dissolve in hot. If
you regularly drink tap water from a building tap that has not had water
running through the pipes for days, it's best to first run off some to
clear the copper piping of water that has been stagnating there for a
long time. Even the cold water pipes.
--
John Savage (my news address is not valid for email)

In article ,
John Savage wrote:
First I've heard of copper dissolving in hot water. How long does it
take for the pipes to disappear?

No one knows; we throw out the HWS as soon as one tiny spot in the copper
coils corrodes all the way through. Wasteful innit?

But often caused by impurities in cheap tube?

--
*Honk if you love peace and quiet.

Dave Plowman London SW
To e-mail, change noise into sound.