An evaluation of conventional cleaning and disinfection and electrostatic disinfectant spraying in K-12 schools

Background: Microbes endemic to student desks can survive for long periods and infect students. The effectiveness of conventional cleaning and disinfection practices and electrostatic disinfectant spraying were examined. Methods: Six K-12 schools in Southeastern Ontario participated in the study. The viable microbial loads on 100 student desks were assessed via Replicate Organism Detection and Counting (RODAC) plates before and after cleaning and disinfection procedures. Results: The adjunctive effect of electrostatic disinfectant spraying was tested on 36 desks. Mean pretest colony-forming units (CFUs) per desk were 126.8 (SD 95.7), after conventional cleaning and disinfection mean CFUs were 73.4 (SD 93.0) (t = 4.0, P = 0.0003), and subsequent electrostatic disinfectant spraying further reduced mean CFUs to 54.2 (SD 85.0) (t = 2.6, P = 0.02). The independent effect of electrostatic disinfectant spraying without an intervening conventional cleaning step was tested on 64 desks. Mean pretest CFUs were 106.4 (SD 94.5) and after electrostatic disinfectant spraying mean CFUs decreased to 62.9 (SD 87.1) (t = 3.3, P = 0.001). Conclusions: Conventional and electrostatic disinfection methods were both effective in increasing the hygienic state of student desks. Electrostatic disinfection spraying improved hygienic state when conducted after conventional cleaning and disinfection and when used independently.