Hygienic safety of alcohol-based hand disinfectants and skin antiseptics

Purpose: The aim of this study was to evaluate the overall risk of hand disinfectants and skin antiseptics to become contaminated with bacterial spores throughout the production process and the subsequent in-use period, hence posing a public health risk. Methods: Microbiological assessment of primary packaging material was carried out and long-term survival of bacterial spores in alcohol was assessed using sporulated B. subtilis ATCC 6633 as a standard. In-use contamination of alcohol-based formulations was tested by repeated use over 12 months under practical conditions and microbiological and physico-chemical data were determined. Results: Among 625 containers analyzed, 542 did not yield any microbial growth. Median colony count for aerobic spore-forming bacteria was 0.2 cfu/10 ml container content. No anaerobic spore-forming bacteria were detected. Additionally, long-term survival of bacterial spores in aliphatic C2–C3 alcohols revealed 1-propanol to reduce the number of spores most effectively, with 2-propanol and ethanol having a somewhat less pronounced impact. In-use tests did not detect any microbial contamination or change in the physicochemical properties of the tested products over 12 months. Conclusions: Our data reveals that state-of-the-art production processes of alcohol-based hand rubs and antiseptics can be regarded safe. Primary packaging material and use were not found to pose a significant contamination risk as far as bacterial spores are concerned. Based on the data from this study, a microbial limit of <1 cfu/10 ml can be suggested as a quality-control threshold for finished goods to ensure high quality and safe products.