Evaluation of Penicylinders Used in Disinfectant Testing: Bacterial Attachment and Surface Texture

Open Access
Publisher Website
Google Scholar
Abstract
Two passible deficiencies in the AOAC use-dilution method for registration of chemical disinfectants by the Environmental Protection Agency are examined: (7) the physical disparities among brands of penicylinders and (2) the variability of bacterial numbers on penicylinders depending upon test strain and penicylinder surface texture. Textual differences of 2 brands of stainless steel penicylinders, one brand of porcelain, and one brand of glass were assessed by scanning electron microscopy. A considerable variation in smoothness of both inner and outer surfaces of stainless steel and porcelain penicylinders was observed. Glass penicylinders were very smooth. Numbers of bacteria attached to a penicylinder were assessed by vortexing the penicylinders 30 s at No. 4 after using the AOAC method of bacterial inoculation and drying 40 min at 37°C. With this methodology, stainless steel carriers retained the 3 AOAC-recommended bacterial test strains differentially: ca 107 for Pseudomonas aeruginosa, 5 x 106 tat Staphylococcus aureus, and 106 for Salmonella choleraesuis; glass retained 10'-107 organisms of all 3 test strains; porcelain retained about that amount of S. aureus but 105-106 P. aeruginosa and 103-104 S. choleraesuis. These data suggest that disinfectants are not similarly challenged with the AOAC-recommended test bacteria and that an alternative method should be considered to ensure comparable numbers of bacteria on penicylinders

This publication has 1 reference indexed in Scilit: