Not drying your hands thoroughly after washing them could increase the spread of bacteria, and rubbing your hands while using a traditional hand dryer could be a contributing factor, according to new research. The research looked at different methods of hand drying, and their effects on transfer of bacteria from the hands to other surfaces. The different methods included paper towels, traditional hand dryer, and a new model of hand dryer, which rapidly blows water from the hands. Our bodies naturally have bacteria all over them. However, bacteria from other sources, such as raw meat, can also survive on hands. They can be easily transferred to other surfaces, increasing the risk of cross-contamination . When the hands are washed, the number of the bacteria on the surface of the skin decreases, but they are not necessarily  _ . If the hands are still damp then these bacteria are more readily transferred to other surfaces. The researchers quantified the effects of hand drying by measuring the number of bacteria on the hands before and after different drying methods. Volunteers were asked to wash their hands and palce them onto contact plates, which were then incubated   to measure bacteria growth. The volunteers were then asked to dry their hands using either hand towels or one of the two hand dryers, with or without rubbing their hands together, and levels of bacteria were re-measured. The researchers found that rubbing the hands together while using traditional hand dryers could cancel out the reduction in bacteria numbers following hand washing. When hands are rubbed together during drying, bacteria that live within the skin can be brought to the surface and transferred to other surfaces, along with surface bacteria that were not removed by hand washing. A resaecher says, "Good hand hygiene  should include drying your hands thoroughly and not just washing . The best method of drying your hands id using paper towels or using a hand dryer which doesn't require you to rub your hands together." The levels of bacteria were re-measured in the research because  _  .
the first measurement was not accurate the second measurement involved ways of hand drying different parts of the hands were measured The two measurements involved different times