Bacteria on Hands
Name: Peter M.
What is the normal amount of single strand of bacteria on
the human hand at any given time. How about the
total amount of bacteria on the human hand?
THe only data I could find was from a study where the
efficacy of hand washing for nurses in an intensive
care unit was studied. The unwashed hands contained an
average of 84 colony forming units (the classical unit
with which we count viable micro organisms) per hand.
The method applied was to determine the amounts of
organisms on the fingertip so I guess this number
should be corrected for the complete surface of the
hand. In 30% of people there were more than 200 CFU
present. You should bear in mind that nurses wash
their hands pretty often anyway. Your hands after
working in the garden, or cleaning the dustbin, would
probably contain a factor 10 or maybe 100 more
organisms. Wet or moist hands release more organisms
than dry hands. The moist factor in part explains why
washed hands (even washed with soap) often show up
with a heavier bacterial load than unwashed hands. But
I couldn't find exact numbers on this.
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Update: June 2012