Hacker News Reader

Comment by jobu | Hacker News Reader

"According to a 2004 EPA sample of 158 planes, 13 percent contained coliform. Two of the airplanes were found to have dangerous E.coli in the water."

That is kinda gross, but realistically all that bacteria would be killed by heating the water.

More of a concern is that is the same tap water in the bathroom for washing hands. Last flight I took I noticed there was a Purell dispenser in the bathroom next to the sink and I wondered why that was necessary given there was soap and water.

View on HN

Simply heating does not kill all bacteria magically. That would require boiling for some time and I doubt that happens in-flight.

Also, 'boiling' at the cabin pressure is not quite normal boiling.

The safe temperature for killing bacteria is about 140°F or 60°C. To get water to boil at that low a temperature requires about ⅕ atmospheric pressure, or roughly the atmospheric pressure outside the aircraft.

yea wilderness survival says full boil for at least 3 minutes, more in higher altitude. While shopping for an on-demand hot water tap, I couldn't find a single one that even went up to boiling temperature, so my hunch is that airplanes don't even boil for a second.

It depends on what you're trying to kill. Some bacteria perish quickly at less-than-boiling temperatures. In the wild, you have spores and other hardy organisms that require a lot more heat and time to kill.

The 3 minutes idea is to kill anything that may be deeply imbedded the bits of wood, leaves, and other detritus suspended in the water.

It's generally considered paranoid overkill when you consider the water will take a while to cool - it will stay in the "kill everything" temperature for quite a while in the process.

https://besurvival.com/guides/how-long-should-you-boil-water

Heat absolutely does kill bacteria. Heating water for just a few minutes at 60C will kill e. coli, 70C will kill it instantly. Coffee is brewed at 90-100C.

[1] https://academic.oup.com/jtm/article-pdf/3/1/11/5107757/jtm3...

Airplanes are not pressurized to sea level though, water boils at lower temperatures at altitude.

On airplanes, pressure is equivalent to about 2000m ASL, at which water boils at 93.4 °C

There are several ski resorts at 2000m, you notice the difference in coffee temperature from sea level.

Yeah, but not "magically".

Some people prefer sanitizer as opposed to soap and water? shrug

Some people prefer free sanitizer to booze.

Doesn't our stomach kill a lot of bacteria with the acid?

Food and drinks pass through other parts of our body before hitting the stomach.

Surprisingly not. How else would your intestinal biome be established unless bacteria passed unharmed through your stomach?

Also, there are lots of diseases such as E. coli infection, etc, that are food borne. Stomach acid doesn't seem to help all that much with those.

Reply on news.ycombinator.com