Evaluation of a Mobile Two-Stage Decontamination System using a Power Washer Combined with Eight Disinfectant Treatments

With the increased frequency of pandemics that threaten the spread of zoonotic diseases associated with agricultural commodities and trade, it is becoming a national priority to advance more effective and efficient decontamination technologies. A field study was conducted to evaluate a two-stage, mobile power washing system. The study factors were power washing, disinfectant type, sample surfaces, and number of repeat disinfectant applications. Study factors were evaluated based on log10 reduction of viable Bacillus subtilis spores on inoculated sample surfaces. Diluted bleach from Clorox Concentrate, applied without power washing, had the greatest sporicidal activity when applied three times to non-porous surfaces (steel washers), which resulted in a 3.0 log10 reduction of viable spores. The two-stage decontamination treatment with the greatest sporicidal activity was power washing porous surfaces (wool fabric), followed by three applications of EasyDECON DF-200, resulting in a 4.8 log10 reduction of viable spores. The results showed that power washing was the most important factor for dislodging spores and overall decontamination effectiveness. Also, sporicidal activity was slightly greater for non-porous surfaces compared to porous surfaces. Repeated applications of disinfectants resulted in little to no improvement in sporicidal efficacy. The results from this field study were comparable with a similar two-stage equipment decontamination study, which was conducted the year before this study. Further research is needed to evaluate large stationary decontamination systems and refine any interactions between power washing parameters and innovative sanitation methods