Efficacy of aerosolized hydrogen peroxide-based sanitizer on the reduction of pathogenic bacteria on a stainless steel surface

Abstract

This study was conducted to investigate the survival rates of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes on stainless steel surfaces at 25 °C and an approximately 70% relative humidity, as well as the efficacy of two concentrations of an aerosolized hydrogen peroxide-based sanitizer on the reduction of the bacterial populations on stainless steel surfaces. Three different strains of bacteria, E. coli O157:H7, L. monocytogenes, and S. Typhimurium, were suspended in phosphate buffer with saline (PBS) or M9 minimal broth, inoculated onto a stainless steel surface and stored at room temperature for seven days or were treated with an aerosolized hydrogen peroxide-based sanitizer at concentrations of 0.25% and 0.5% for 0, 15, 30 and 60 min. Initial bacteria levels before storage were 105–6 CFU/coupon for E. coli O157:H7 and S. Typhimurium and 104–6 CFU/coupon for L. monocytogenes. The populations decreased as the storage time increased. However, the rates of reduction before and after storage varied greatly depending on the bacterial strain. Generally, levels of E. coli O157:H7 were highly reduced during storage compared to those of S. Typhimurium and L. monocytogenes. The survival rate of the pathogens on the stainless steel surface was higher when M9 minimal broth was used than with PBS. Treatments with aerosolized hydrogen peroxide-based sanitizer were effective at reducing the levels of pathogens on the stainless steel surfaces. Levels of the three pathogens were below the detection limit (1 log CFU/ml) after 60 min with the 0.25% concentration. When the 0.5% sanitizer was used, levels of E. coli O157:H7 were below the detection limit after 15 min, and levels of L. monocytogenes and S. Typhimurium were reduced to below the detection limit after 30 and 60 min, respectively. These results suggest that the survival rates of pathogens on surfaces such as stainless steel vary depending on the bacterial strains and conditions, and that aerosolized hydrogen peroxide-based sanitizer are effective to remove these pathogens from surfaces.