Is Liquid Soap Safer Than Bar Soap?
There have only been occasional studies done comparing the benefits of liquid soaps and bar soaps. But no matter how sporadic, the findings were all the same. According to New York Times reporting, liquid soaps are no safer than bars, despite perception that bar soaps are more likely to spread germs in a public restroom.
According to the article, the most rigorous study comparing liquid to bar soaps was published 53 years ago, in 1965. At that time, scientists conducted a series of experiments in which they intentionally contaminated their hands with about five billion bacteria.
The scientists then washed their hands with a bar of soap and had a second person wash with the same bar of soap. They found that bacteria were not transferred to the second user and concluded: “The level of bacteria that may occur on bar soap, even under extreme usage conditions (heavy usage, poorly designed non-drainable soap dishes, etc.), does not constitute a health hazard.”
A similar study conducted in 1988 confirmed these earlier findings. Researchers inoculated bars of soap with E. coli and Pseudomonas bacteria and had 16 people wash their hands with the contaminated bars. No detectable levels of bacteria were found on their hands. The study concluded that “little hazard exists in routine hand washing with previously used soap bars.”
Additional studies have been done over the years where environmental bacteria has been found on bar soaps, as well as the surface of liquid soaps. But, none have shown to be a source or risk of infection.
According to an article on How Stuff Works, there is no real difference between liquid and bar soaps. In fact, all types of soap are composed of the same essential components — alkali salts of fatty acids and detergent properties.