食品取扱者における手洗いの細菌学的検査結果の疫学的解析および食材取扱い後の手洗い等の検証

抄録

We conducted an epidemiological analysis of bacteriological test results (N = 44,218) from hand swabs collected after hand washing from 2017 to 2023 to understand the hand hygiene practices of food handlers at work and assess the impact of routine hand sanitization during the COVID-19 pandemic. The Mean and standard deviation of standard plate count (SPC) was 2.70±1.01 log10 CFU per swab, with coliform (CF) and Staphylococcus aureus (SA) positive rates at 2.24% and 4.22%, respectively. Swabs collected from gloves worn by food handlers showed significantly lower SPC than those collected from bare hands. Positive rates for CF and SA were higher in cases involving “long nails” and “wounds or rough hands,” respectively. Mean SPC values were higher in swabs from CF- or SA-positive cases than in swabs from negative cases. Variations in the mean SPC values and positive rates for CF and SA were observed across different categories of food facilities. Both the mean SPC values and positive rates for CF and SA increased during the summer months (July to September). The mean SPC values and CF-positive rates decreased during the COVID-19 pandemic, whereas the SA-positive rates increased. In a laboratory experiment assessing various hand hygiene methods after handling foodstuffs naturally contaminated with microorganisms, “hand rubbing with alcohol” was found to be the most effective, followed by “adequate hand washing” and “inadequate hand washing.” The log reduction in SPC was greater for individuals working as sanitation inspectors who were highly experienced in hand washing than for others. The mean SPC values and distribution for “adequate hand washing” were similar to those observed in food handlers after hand washing. These findings provide valuable scientific data for hand hygiene instruction.