Inactivation Rate of Specific Microorganisms Inoculated onto Mica and Stainless-Steel Carriers

Abstract

Human pathogenic viruses and bacteria can be transmitted by touching of inanimate objects. The goal of this study was to determine if a high-energy surface would result in a more rapid inactivation of viruses and bacteria. The rate of inactivation of MS2 virus, Escherichia coli and Enterobacter aerogenes were compared on mica and stainless-steel carriers. Each carrier was inoculated with 0.025 mL solution containing MS2, E. coli, or E. aerogenes suspended in 0.85% saline and dried for interval contact times of 0, 10, 15, 30, 60 minutes. The organisms were then harvested with a polyester swab pre-moisten in 2 mL of 0.85% saline solution and later assayed for plaque or colony counts. Plaque and colony counts recovered from mica were lower than those of stainless-steel carriers. E. coli had complete inactivation prior to 10 minutes of contact on mica. E. aerogenes had minimal inactivation difference between the two carrier types but no colonies were found after 60 minutes of contact time. MS2 recovery on mica was half of stainless-steel. It is postulated that inactivation rates on mica vs stainless-steel were more rapid due to the high-energy surface properties of the mica. With adequate progress in research, mica development could function as a measure of protection from contaminants when sanitation fails (Wilks, Michels, & Keevil, 2005).