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*
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newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.