The general pattern with these sorts of things is that it's a combination of temperature and time. For any given microorganism there's some temperature it thrives at, some temperature at which it will start dying and if left for long enough will completely kill it off, and some temperature at which you can be assured that even brief exposure will completely kill it off.
Most microorganisms start dying above 50C (122F) or so. Roughly an hour at 50C should sufficiently pasteurize water for drinking. Or around 15 minutes at 60C and so forth. As the temperature increases the required time decreases. The common advice to boil water to render it safe for drinking is conservative and is given for a number of reasons: to err on the side of caution; because there are extremophiles that can survive at higher temperatures; because water boiling is an easily visible cue; and because by the time water reaches boiling it is sterilized so there's no need to time it (which is something people can screw up).
I found two sources on the temperature resistance of Naegleria fowleri. First the CDC [0] says it grows best at 46C (115F) and survives minutes or hours at 50-65C (122-149F). I also found a paper [1] which showed no detectable Naegleria fowleri after pasteurization at 68C (154F), unfortunately it didn't give a time though.
The upshot of all this is that Naegleria fowleri is somewhat temperature tolerant but isn't an extremophile; it's killed off on a temperature-time scale that's reasonably typical for water-borne pathogens. By the time water reaches 95C (203F) it is 100% dead and probably was already by the time the water reached 70-80C (158-176F).
> For nasal rinsing, the CDC recommends using boiled, sterile, or distilled water. "If tap water is used, it should be boiled for a minimum of 1 minute, or 3 minutes in elevations >1,980 meters, and cooled before use,"
I wonder how they came to those numbers; on a typical stove, if you heat a pot of water to boiling, and then immediately let it cool off, it will spend almost 3 minutes at (or above) 200F (the boiling point of water at 1980 meters) so the sea-level recommendation seems more conservative than the altitude recommendation.
dkbrk|1 year ago
Most microorganisms start dying above 50C (122F) or so. Roughly an hour at 50C should sufficiently pasteurize water for drinking. Or around 15 minutes at 60C and so forth. As the temperature increases the required time decreases. The common advice to boil water to render it safe for drinking is conservative and is given for a number of reasons: to err on the side of caution; because there are extremophiles that can survive at higher temperatures; because water boiling is an easily visible cue; and because by the time water reaches boiling it is sterilized so there's no need to time it (which is something people can screw up).
I found two sources on the temperature resistance of Naegleria fowleri. First the CDC [0] says it grows best at 46C (115F) and survives minutes or hours at 50-65C (122-149F). I also found a paper [1] which showed no detectable Naegleria fowleri after pasteurization at 68C (154F), unfortunately it didn't give a time though.
The upshot of all this is that Naegleria fowleri is somewhat temperature tolerant but isn't an extremophile; it's killed off on a temperature-time scale that's reasonably typical for water-borne pathogens. By the time water reaches 95C (203F) it is 100% dead and probably was already by the time the water reached 70-80C (158-176F).
[0]: https://www.cdc.gov/parasites/naegleria/pathogen.html
[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5057267/
gerikson|1 year ago
> For nasal rinsing, the CDC recommends using boiled, sterile, or distilled water. "If tap water is used, it should be boiled for a minimum of 1 minute, or 3 minutes in elevations >1,980 meters, and cooled before use,"
aidenn0|1 year ago