From Craig Webster
Your Patents column mentions inventor Raymond Johnson’s claim that millions
of cases of food poisoning in the food industry and cross-infection in hospitals
result from improperly washed hands
(This Week, 12 December 1998, p 11).
However, it has been known for some time that drying your hands is more
important than washing them. Wet, well-washed hands can transmit as many as 60
000 microorganisms on contact, whereas similarly washed hands that have been
thoroughly dried transmit a mere 200—this from a study reported in
Antipodes in your Australian edition
(“Wet hands given a towelling”, 13 June 1998, p 50).
Moisture is an effective medium for the transfer of microorganisms, and since
it is almost impossible to get hands absolutely clean, stopping the bugs being
transferred to other surfaces is a more effective way of dealing with the
problem than washing per se. Ideally, hands should be dried with a towel
followed by hot air drying.
Johnson’s patented device for detecting improperly washed hands using
coloured soap and a video camera would do better if set up to detect improperly
dried hands—something which is surely within the capabilities of the same
technology.
Advertisement
Auckland, New Zealand
