Efficacy of novel aqueous photo-chlorine dioxide against a human norovirus surrogate, bacteriophage MS2 andClostridium difficileendospores, in suspension, on stainless steel and under greenhouse conditions

摘要

Aims The efficacy of a novel photochemical method for generating chlorine dioxide (photoClO(2)) was evaluated against human noroviruses (HuNoV) surrogate, bacteriophage MS2, andClostridium difficileendospores. Methods and Results Chlorine dioxide was generated by mixing 1% sodium chlorite with 10 parts-per-million (ppm) Eosin Y and irradiating with a photo-activator-excitable light. PhotoClO(2)efficacy was assessed against bacteriophage MS2 andC. difficileendospores in suspension, on hard surfaces and greenhouse conditions under soiled and unsoiled conditions. The estimated effective photoClO(2)produced and consumed was 20 center dot 39 +/- 0 center dot 16 ppm at a rate of 8 center dot 16 ppm per min in a 1% sodium chlorite solution. In suspension, MS2 phage was reduced by 3 center dot 35 and >5 center dot 10 log(10)PFU per ml in 120 and 90 min, with and without soil, respectively. At the same time, when dried on stainless steel surface, MS2 phage was reduced by >4 center dot 53 log(10)PFU per carrier in 30 min under both conditions. On the other hand,C. difficileendospores in suspension were reduced by 2 center dot 26 and 3 center dot 65 log(10)CFU per ml in 120 min with and without soiling, respectively. However, on stainless steel surface, maximal reductions of theC. difficileendospores were 0 center dot 8 and 1 center dot 5 log(10)CFU per carrier with and without soiling, respectively, and a maximal reduction of 2 center dot 97 log(10)CFU per carrier under greenhouse conditions at 24 h. Conclusions Overall, photoClO(2)showed promise as a technology to control HuNoV contamination on environmental surfaces but requires further optimization and testing againstC. difficileendospores. Significance and Impact of the Study Results from this investigation will serve as a model for how to generate and quantify photoClO(2)and how to appropriately evaluate this new class of disinfectants against environmentally resilient pathogens: viruses and bacterial endospores.