Q. Is bar soap a possible source of bacteria? Is it better to use liquid soap?
A. Soggy bar soap can become contaminated with bacteria. But not all liquid soap is free of germs. Microbiologist Charles Gerba, PhD, has found that refillable liquid soap dispensers (such as those found in many public rest rooms) can become heavily contaminated with fecal bacteria. Facilities that used sealed plastic bags of liquid soap in their dispensers had no contamination.
Thoroughly rinsing your hands after scrubbing them should help get rid of bacteria and viruses, regardless of the type of soap you use.