from the article posted by Ren:

"Because the time required to heat water from a temperature of 55°C to a boil works toward disinfection, any water that is brought to a boil should be adequately disinfected. Boiling water for 1 min or keeping water covered and then allowing it to cool slowly after boiling can add an extra margin of safety [37]. The boiling point decreases with increasing altitude, but this is not significant when compared with the time required to achieve thermal death at these temperatures."

Short boiling times, especially when slow cooling is employed, would seem to be adequate.

Thanks a bunch for this very thorough discussion!