Friday, February 09, 2007

Urban legend: water is less healthy than wine

Received this email from a friend today:
It has been scientifically proven that if we drink 1 liter of water each day, at the end of the year we would have absorbed more than 1Kg of Escherichia coli (E. coli) bacteria found in feces. In other words, we are consuming 1 kilo of Poo. However, we do not run that risk when drinking wine (or rum, whiskey, beer or other liquors) because alcohol has to go through a distillation process of boiling, filtering and fermenting and alcohol kills E.coli
WINE = Health

As a microbiologist, I feel compelled to shoot down this blatant attack on drinking water quality.
The math doesn't add up.
1 bacteria = 10-12 kg (very roughly)
1 kg of bacteria = 1012 cells
1 liter of water per day = 365 liters
1012 cells / 365 liters = 2.7 x 109 cells per liter
Waaaaaaaaaaay higher than the bacterial load found in tap water even in the developing world, by many orders of magnitude. If a liter of water had this many bacteria in it, the water would be visibly cloudy. Even if you drank water with such a high bacterial load, you are surely drinking a mixed population and not a pure E. coli solution.

So there.

Hypertextbook: Mass of a Bacterium: "A typical mass of a bacterium would be about 10-12 g or one picogram (pm)."
Lawrence Berkeley National Laboratory: "E-coli concentrations in unsanitary drinking water at various developing world sites are typically found to exceed thousands per 100 milliliters (e.g., 30,000 per 100 ml reported at a site near Pune, India). The WHO standard specifies less than 1 per 100 ml for good drinking water quality, which is also the standard used in the industrial world drinking water supply."
US EPA Drinking Water standards state that heterotrophic bacteria should not exceed 500 CFU per ml.
"Heterotrophic plate counts and drinking-water safety" from World Health Organization: "Exposure to general HPC microbiota is far greater through foodstuffs than through drinking-water."


  1. I love it. This is like Myth Busters, Jenny style.

  2. Oh god... I feel compelled to make an confession...

    I'm not sure if you are a stat-hawk like myself and many other bloggers I know, but if you are, I apologise for the bizzare search string that might be appearing about now.

    If you see a search string in your stats which reads 'how many poo per day is healthy', well, that was me.

    I have no idea why a search for that brought up this particular post, but it did.

    In my defense, it was for genuine medical reasons I was searching, and my syntax is normally better that that - I was trying to use simple cases to get better google results.

    Anyway... The reason I have to confess is I've seen equally odd strings in my stats, and I always wonder why people ended up on my site from such odd searches.

    Anyway... I'm wittering now.

    Nice blog... sorry for my unorthodox intrusion!

  3. was meant to be a JOKE not a science fact...GEEZ...u really need to chill out a tiny bit. LOL--the friend that sent it!