susceptibility of ultra-bacteria to heat?

gerne at my-deja.com gerne at my-deja.com
Sat Jul 10 19:02:47 EST 1999

In article <slrn7o6pp7.7s2.soma at amanda.dorsai.org>,
  soma at iii.dorsai.org (*selah*) wrote:
> I was wondering if the "ultra"-bacteria (bacteria the size of viruses
> as crytosporidium, etc.) are as resistant to heat sterilization as
> bacteria - i.e. needing 120 degrees C for 20 minutes - or if it's like
> viruses needing only 80 degrees C for a minutes or so.
> Thanks.
> --
> Remove iii from address to reply.
You mix up a few things here. Cryptosporidium is not a virus and quite a
bit bigger than common bacteria, let alone a virus. It's resistant
against a number of treatments actually as an oocyst, spore type state.

Heat resistance is inverse proportional to the biological activity of an
organism, such as high sensitivity in exponential growth, low in
stationary and starvation conditions. A big killer in heat injury
at lower temperatures comes from the cells own metabolism as indirect
cell damage. If they show active respiration they lose their protection
against intrinsic oxidative injury whilst normally the built-up of
respiration is coupled to oxidative protection.

At higher temperatures direct denaturation of cellular components takes
place unless the organism has found clever ways of protecting it's
structures such as for example in spores.

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