Microbiological Evaluation of the Efficacy of Soapy Water to Clean Hands: A Randomized, Non-Inferiority Field Trial. Am J Trop Med Hyg. 2014 Jun 9.
Amin N1, Pickering AJ2, Ram PK2, Unicomb L2, Najnin N2, Homaira N2, Ashraf S2, Abedin J2, Islam MS2, Luby SP2.
Author information
1International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh; Stanford University, Stanford, California; University at Buffalo, Buffalo, New York; Centers for Disease Control and Prevention, Atlanta, Georgia nuhu.amin@icddrb.org.
2International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh; Stanford University, Stanford, California; University at Buffalo, Buffalo, New York; Centers for Disease Control and Prevention, Atlanta, Georgia.
Abstract
We conducted a randomized, non-inferiority field trial in urban Dhaka, Bangladesh among mothers to compare microbial efficacy of soapy water (30 g powdered detergent in 1.5 L water) with bar soap and water alone. Fieldworkers collected hand rinse samples before and after the following washing regimens: scrubbing with soapy water for 15 and 30 seconds; scrubbing with bar soap for 15 and 30 seconds; and scrubbing with water alone for 15 seconds.
Soapy water and bar soap removed thermotolerant coliforms similarly after washing for 15 seconds (mean log10 reduction = 0.7 colony-forming units [CFU], P < 0.001 for soapy water; mean log10 reduction = 0.6 CFU, P = 0.001 for bar soap). Increasing scrubbing time to 30 seconds did not improve removal (P > 0.05). Scrubbing hands with water alone also reduced thermotolerant coliforms (mean log10 reduction = 0.3 CFU, P = 0.046) but was less efficacious than scrubbing hands with soapy water. Soapy water is an inexpensive and microbiologically effective cleansing agent to improve handwashing among households with vulnerable children.
