In your patents column you claim that millions of cases of food poisoning in the food industry and cross-contamination in hospitals result from improperly washed hands. However, it has been known for some time that drying your hands is actually more important than washing them. Wet well-washed hands can transmit as many as 60,000 micro-organisms on contact, whereas similarly washed hands which have been throughly dried transmit a mere 200 - this from a study reported in your own Forum section (Wet hands given a towelling, 13 June 1998). Wash'n'dry
Moisture acts as an effective medium for the transfer of bugs and since it is almost impossible to get hands absolutely clean, stopping the bugs transferring is actually 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. Raymond Johnson's patented device for detecting improperly washed hands using a computer and a camera would do better if set up to detect improperly dried hands - something which would surely be within the capabilities of the same technology.
Craig Webster
Reference
- "Washed up" New Scientist 1999; 160(2164): 11.
