Comparison of two plain soap types for removal of bacteria and viruses from hands with specific focus on food service environments.

Handwashing (HW) is a long established and widely accepted method to prevent disease transmission. Ensuring effectiveness of current HW methods is essential for the optimization of HW and enhanced disease prevention. The objective of this research was to determine the difference in microbial reduction between plain foaming and liquid handsoap. The hands of 24 participants were inoculated by the palmar surface method with an average of 1.25 × 10 8 CFU Escherichia coli C3000 or 1.36 × 10 8 PFU MS2 bacteriophage. Participants washed their hands following a standard protocol with a standardized soap volume and a 10 s HW time. A glove juice method was used to recover microorganisms from hands. Remaining microorganisms were quantified by standard spread plate and plaque assays for E . coli and MS2, respectively. Hands inoculated with E . coli had an average log reduction of 2.76 ± 0.70 and 2.52 ± 0.58 log CFU for foaming and liquid handsoap, respectively. The mean log reduction for hands inoculated with MS2 was 2.10 ± 0.57 and 2.23 ± 0.51 log PFU for foaming and liquid handsoap, respectively. Data indicate no significant difference in overall microbial removal when comparing the efficacy of plain foaming and liquid handsoap. However, regardless of soap type, the type of microorganism impacted overall log reduction with a greater reduction for E . coli when compared to MS2 with a significant difference (p = 0.0008) in reduction for foaming handsoap. This study is the first comparison of the efficacy of plain liquid and foaming handsoap for microbial reduction on hands during HW. [ABSTRACT FROM AUTHOR]