Besides raw materials, primary packaging was identified as a potential source of bacterial spores. Investigation of a total of 625 containers did not yield any microbial growth in 542 cases. 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 was investigated. 1-propanol was found to reduce the number of spores most effectively, with 2-propanol and ethanol having a somewhat less pronounced impact. Thus 1-propanol was found to give reduction rates of 1.35 lg after 7 weeks contact time at a concentration of 30% (v/v), and viability of B. subtilis spores was further decreased to > 1.5 lg by 30% (v/v) 1-propanol after 14 weeks.
Exemplary in-use tests of a typical hand disinfectant and a typical skin antiseptic did not detect any microbial contamination or change in the physico-chemical properties of the tested products over 12 months.