Americans aren't washing their hands nearly as often and as thoroughly as they should, according to a recent study. But the recommendations they are defying aren't squeaky clean.
squeaky：发出吱吱响的 inconspicuous：不显眼的，不引人注意的 groom：打扮，新郎，马夫
For the study, 12 researchers fanned out across public bathrooms in East Lansing, Mich. Trying to keep as inconspicuous as is possible while loitering in restrooms for instance, pretending to groom themselves at the sinks they recorded the behavior of more than 3,700 bathroom users.
The results were discouraging: One in 10 didn't wash their hands at all; just two in three used soap; and just one in 20 washed their hands for at least 15 seconds, which is five seconds shy of recommendations from the U.S. Centers for Disease Control and Prevention.
The researchers, in the study and in the resulting press coverage, said the implications for public health were dire. No wonder roughly 50 million Americans contract food-borne illnesses each year, this argument goes, when so many people aren't washing their hands. 'The public needs to be continually encouraged to engage in proper hand-washing practices,' the authors, from Michigan State University's School of Hospitality Business, concluded.
dire：可怕的，悲惨的
Other scientists in the surprisingly rich field of hand-washing research, though, said the study's findings weren't necessarily a call to public-health action. For one thing, the study took place in restrooms in a college town, which may not be representative of all public toilets in the U.S. Various factors such as the state of the bathrooms could skew the results with such a limited sample. 'It's clumped data and should be treated as such,' said Valerie Curtis, director of the Hygiene Centre at the London School of Hygiene & Tropical Medicine.
Lead author Carl P. Borchgrevink, associate professor at Michigan State's hospitality school, responded that while there is room for further research, he sees no reason the findings wouldn't apply to settings similar to those observed.
Washing hands also isn't as vital after urinating as after defecating, some researchers say. 'This is because pathogens are found in feces,' said Gaby Judah, a graduate student at the London School of Hygiene & Tropical Medicine.
urinating：小便 defecating：澄清，粪便 pathogen：病原体
Asked about the importance of washing for 20 seconds, and whether there are diminishing returns after a certain period, Prof. Borchgrevink said those were 'great questions, however, I am a hospitality-business professor, and am not able to answer with authority.' He referred inquiries to the CDC.
CDC guidelines for hand-washing time aren't based on a lot of hard data. The agency used to advise humming 'Happy Birthday' once while washing, but within the past decade changed that to twice which takes Prof. Borchgrevink, and this columnist, closer to 30 seconds than 20.
'There's no more evidence for that than once,' said Elaine L. Larson, associate dean for research at the Columbia University School of Nursing in New York.
A CDC spokeswoman said no one was available to comment on the CDC recommendations during the holiday week.
No researchers say washing is harmful, or that washing for longer is worse than washing for less time. But many researchers say time is just one of many factors in effective hand-washing. Also critical is the amount of friction applied.
There's also a risk in setting too big of a target for washing time. 'If we set a goal that may appear optimal based on hospital surgical scrubbing, we risk making recommendations that are so unrealistic people will ignore them,' said Stephen Luby, a public-health researcher at Stanford University.
surgical scrubbing：外科擦洗
That leaves much room for debate on how much soap matters, for example. 'While it is good to wash hands for the recommended time, using soap in the first place is the most important part,' said Ms. Judah. But Prof. Luby said work that he and his colleagues conducted in rural Bangladesh in 2007 showed that 'even rinsing with water alone provides important health benefits.'
rinsing：冲洗，漱口
Then again, the picture could be even worse than the Michigan State study suggests. Some people who noticed they were being observed may have washed their hands only to avoid being seen leaving a bathroom without doing so.
'There is social pressure around this idea that we should clean our hands,' Prof. Luby said. 'It's part of being a civilized person.'