Health advice on hand sanitizers
Antibacterial hand sanitizers (免洗洗手液) are marketed as a good alternative (替代品) when soap and water are not available. Manufacturers say that their sanitizers kill 99. 9 percent of germs (细菌) , but research suggests that this not the case.
How do hand sanitizers work?
Most sanitizers are alcohol-based; they work by removing the outer layer of oil on our skin, then the alcohol kills the bacteria.
However, Barbara Almanza, associate professor at Purdue University, notes that hand sanitizers do not significantly reduce the amount of bacteria, and in some cases, can increase it.
So the question arises, how can manufacturers say sanitizers kill 99. 9 percent of bacteria?
How can manufacturers make the 99. 9 percent claim (声称) ?
Manufacturers test their products on bacteria-tainted surfaces. In this controlled environment, hand sanitizers do kill 99. 9 percent of bacteria. However, the human hand is a lot more complex and goes through a lot of different changes in a day compared to a controlled surface.
These tests allow manufactures to obtain consistent results. But, in reality, how effective are hand sanitizers in killing bacteria in everyday life?
Hand sanitizer VS hand soap and water
Almanza says that soap and water are the best way to clean your hands. Hand sanitizer cannot and should not be a direct replacement.
However, they are a useful alternative. To effectively kill bacteria, studies recommend that people use sanitizers that are at least 60 percent alcohol. Also, sanitizers won't work if you have dirty hands, so wipe them with a tissue or napkin before sanitizing.
What about antibacterial soaps?
Research has shown that regular soap is just as effective as antibacterial soap in reducing bacteria-related illnesses.
In fact, some consumer antibacterial soap may increase some bacteria's resistance to antibiotics (抗生素) , making them more dangerous.
Other studies show that overly clean environments will negatively affect children by preventing their immune (免疫的) system development. Children need to fight off common germs to develop their immune systems.
