A Comparison of Hand Cleansers' Abilities to Decrease Bacterial Contamination

This experiment used canine fecal contamination to compare water, liquid hand soap, liquid antibacterial hand soap and hand sanitizer, in their abilities to decrease total and enteric coliform bacterial levels.  It was hypothesized that bacterial contamination would be similarly reduced for hand soap and antibacterial hand soap, followed by hand sanitizer then water.  Latex squares were contaminated using a feces and sterile saline solution.  Liquid hand soaps were hand lathered into each sample for 20 seconds using 2.50cc of cleanser and rinsed in warm running tap water for 10 seconds.  Water samples were manipulated for 20 seconds and rinsed for 10 seconds.  Hand sanitizer was applied and the latex manipulated until dry.  Nothing was done to the controls.  After each square was placed on an agar plate for 60 seconds, and 100 µl of sterile water was applied, the spread plate method was performed.  The plates were incubated at 38.3°C for 48 hours and CFUs (colony forming units) were recorded.  Statistical significance could not be proven for all cleansers against control.  However, hand sanitizer had lower total bacterial contamination with 144 CFUs.  Antibacterial hand soap had 238 CFUs, hand soap 605, and water 1566.  For enteric coliform lactose positive growth, hand soap showed more effectiveness with 3 CFUs total.  Water had 44 CFUs, antibacterial hand soap 54, and hand sanitizer 257.  This research would support the conclusion that the benefits of antibacterial hand soaps in decreasing bacterial contamination do not outweigh the risks of increased bacterial resistance and hormonal effects.