Reality Check for Handwashing Practices and Guidance for Its Monitoring

Introduction: Lack of proper handwashing techniques by food handlers remains an unresolved issue in the food industry. Handling food products with improperly washed hands poses a food safety hazard that often does not go through comprehensive review and monitoring compared to other likely to occur hazards. Food manufacturers face an uphill task in determining critical control points, establishing critical limits, and monitoring procedures for employee’s hands.

Purpose: The purpose of this study is to provide guidance to food manufacturers for development of monitoring program(s) for employee’s hands. Specifically, this study will analyze the effectiveness of hand washing frequency and duration, quality of hand washing soaps, and different hand swabbing tools and techniques.

Methods: Twelve subjects were used for this study.  They were allocated to (i) handwashing for up to 8 times per day, (ii) handwashing for <10 sec, 30 sec, and >60 sec.  The dominant hand of each subject was swabbed from (i) tip of the fingers to bottom of the wrist and (ii) palm only, using cellulose sponge, polyurethane sponge, and letheen broth swabs.  The collected samples were enumerated for aerobic plate count (APC), Enterobacteriaceae (EB), Staphylococcus aureus, yeast, and mold. AOAC petrifilm methods were used for all bacterial enumeration. 

Results: In general, no significant difference was observed in bacterial recovery among different swabbing tools. At <10 sec handwashing, APC was 3.31 log for the letheen swabs, 3.63 log for the cellulose sponge, and 4.02 log for the polyurethane sponge.  However, the swabbing area played a significant role in APC recovery: the palm had 2 logs less APC than the whole hand with fingers. Enterobacteriaceae, S. aureus, and yeast were not detected whereas mold was detected on very few subjects.

Significance: This study guides food manufacturers on how to establish effective handwashing practices, develop means of control, and result interpretation with the main goal of creating a 365-degree environmental monitoring program and subsequently safe food production environment.