Comparative Efficacy of Hand Wash Lather Times of 5 to 20 Seconds vs. Alcohol-Based Hand Sanitizer Application Approaches by an In Vivo Cross-Contamination Test Method

Hand hygiene is fundamental in reducing foodborne illness risk, yet current guidance in the U.S. Food and Drug Administration (FDA) Food Code may not fully reflect evidence on product performance or realistic foodservice practices. This study evaluated the in vivo effectiveness of a commercially available nonantibacterial foaming hand wash and an alcohol-based hand sanitizer (ABHS) in reducing bacterial load on hands and transfer to food. Twelve subjects were tested using ASTM E2784 with Escherichia coli (ATCC #10536) as the challenge organism. All subjects used a consistent, standardized technique for each condition. Hand wash was assessed at 5-, 15-, and 20-s lather durations, while ABHS was tested at one dose and with two doses and paper towel use ("SaniOnce"). Mean log10 reductions on hands and bacterial transfer to melon balls were measured. Hand wash always produced substantial reductions, with no significant differences (p > 0.05): mean log reductions were 2.95, 2.86, and 3.00, with corresponding mean transfers of 4.85, 4.76, and 4.64 for 5-, 15-, and 20-s, respectively. ABHS interventions demonstrated superior efficacy (p ≤ 0.05). A single ABHS dose achieved a mean log reduction of 4.06 with transfer of 2.58, while SaniOnce yielded the greatest effect (4.99 reduction, 1.88 transfer). Results suggest that well-formulated hand washes can be effective even at shorter lathering durations, and ABHS provides greater antibacterial efficacy on lightly soiled hands. These findings support modernizing the FDA Food Code guidance to allow situational use of ABHS independently in foodservice settings and to allow shorter wash times when good handwashing technique is practiced.