Microbial Safety of Different Hand-Drying Methods: A Case Study on Electric Warm-Air Hand Dryer and Paper Towel in a Food Processing Company

Abstract

Background: Electric hand dryers are installed in many food processing facilities as a low-cost and low-waste alternative to paper towels at staff hand-hygiene checkpoints. However, there is concern that these electric hand-dryers serve as reservoirs that dispersers microorganisms onto washed hands during the drying of the hands. This is a major concern because after handwashing and drying, food handlers enter the production floor, believing their hands are free of microorganism. This study compared the microbiological safety of an electric warm-air hand dryer and a paper towel dispenser within a food processing facility.

Method: A total of 40 samples were collected over five consecutive periods of continuous use from January to May, 2026. After a standardized handwashing procedure, hand swabs (touch plate method) were collected following drying with each method and cultured for total viable count, yeast and mould, total coliforms, and Escherichia coli.

Results: Data collected were cleaned in Microsoft Excel 2019 and analyzed using IBM SPSS v27 and Python 3.12.3. ArcMap 10.8.2 was used to generate the sampling area. Hands dried with paper towels yielded zero recoverable colonies across all 20 samples. Hands dried with the electric warm-air dryer carried significantly higher total viable counts and yeast/mould counts (Mann-Whitney U=360, p<0.001, r=-0.80 for both), with a mean count of 578± 523 CFU/g for PCA and 1,620 ±1,888 CFU/g for MEA. Overall contamination for detectable growth on any medium was 80% for the electric warm-air hand dryer and 0% for paper towels.

Conclusion: These findings indicate that hand dryer-associated contamination accumulates predictably with dwell time after filter installation, which suggests scheduling filter replacement after every two days if the electric warm-air hand dryer is to be used and for hand-hygiene prerequisite programmes under a food safety management system (FSMS).