Really interesting debate and very informative OP
Just to add a bit in to the debate on altitude and sterilization (I don't know a huge amount about this but have a little knowledge as I started out many moons ago working as an industrial microbiologist).
Killing bacteria with low temperatures is not effective, for most bacterial groups its not the temperature but how they get there that causes them problems. We used to have a "culture store" for isolated strains of bacteria, this consisted of a giant freezer at -74degC. Routinely we would store bacteria for up to 2-3years in this then successfully re-culture them. This is because rapid freezing prevents the formation of the ice crystals that puncture the bacterial cell and kill it. So be careful as cold may only mean dormant bacteria which when warmed will begin to metabolise.
In terms of heating to sterilize at altitude this is effective against bacteria even at 70degC as if the water in your pot is boiling so is the water in the bacterial cell rupturing and disrupting it. Caveat - for most common types of waterborne bacteria there are many that can survive this, thermophilic types if my memory serves me correctly can survive up to 122 degC. This is one of the reasons industrial labs use high pressure autoclaves. Bacteria themselves once water is boiled aren't such a problem (as someone else posted) at lower temps the problems can be the toxins they may leave behind as these might not be de-natured with short boiling times.
Virus's another storey all together...
A one of the things you can do is always boil a pot with the lid on... this will increase the temperature within the pot and the pressure slightly (also holding in steam which is a fantastic sterilizing agent as it kill micro-organisms by giving up its energy quicker than the cell can absorb). I read in a book some time back about a tribe somewhere or other that actually seal the lids of their boiling pots with clay to increase the pressure and when the lid blows off the water is done (not sure how safe this is ).
Its been a long time since I have done anything to do with this so I may be mistaken... either way though its made my brain hurt...
Just to add a bit in to the debate on altitude and sterilization (I don't know a huge amount about this but have a little knowledge as I started out many moons ago working as an industrial microbiologist).
Killing bacteria with low temperatures is not effective, for most bacterial groups its not the temperature but how they get there that causes them problems. We used to have a "culture store" for isolated strains of bacteria, this consisted of a giant freezer at -74degC. Routinely we would store bacteria for up to 2-3years in this then successfully re-culture them. This is because rapid freezing prevents the formation of the ice crystals that puncture the bacterial cell and kill it. So be careful as cold may only mean dormant bacteria which when warmed will begin to metabolise.
In terms of heating to sterilize at altitude this is effective against bacteria even at 70degC as if the water in your pot is boiling so is the water in the bacterial cell rupturing and disrupting it. Caveat - for most common types of waterborne bacteria there are many that can survive this, thermophilic types if my memory serves me correctly can survive up to 122 degC. This is one of the reasons industrial labs use high pressure autoclaves. Bacteria themselves once water is boiled aren't such a problem (as someone else posted) at lower temps the problems can be the toxins they may leave behind as these might not be de-natured with short boiling times.
Virus's another storey all together...
A one of the things you can do is always boil a pot with the lid on... this will increase the temperature within the pot and the pressure slightly (also holding in steam which is a fantastic sterilizing agent as it kill micro-organisms by giving up its energy quicker than the cell can absorb). I read in a book some time back about a tribe somewhere or other that actually seal the lids of their boiling pots with clay to increase the pressure and when the lid blows off the water is done (not sure how safe this is ).
Its been a long time since I have done anything to do with this so I may be mistaken... either way though its made my brain hurt...