Efficacy of EPA-registered disinfectants against two human norovirus surrogates and Clostridioides difficile endospores.

Aims: To determine the efficacy of a panel of nine EPA-registered disinfectants against two human norovirus (HuNoV) surrogates (feline calicivirus [FCV] and Tulane virus [TuV]) and Clostridioides difficile endospores.

Methods And Results: Nine EPA-registered products, five of which contained H O as active ingredient, were tested against infectious FCV, TuV and C. difficile endospores using two ASTM methods, a suspension and carrier test. Efficacy claims against FCV were confirmed for 8 of 9 products. The most efficacious product containing H O as ingredient achieved a >5.1 log reduction of FCV and >3.1 log reduction of TuV after 5 min, and >6.0 log reduction of C. difficile endospores after 10 min. Of the five products containing H O , no strong correlation (R  = 0.25, p = 0.03) was observed between disinfection efficacy and H O concentration. Addition of 0.025% ferrous sulphate to 1% H O solution improved efficacy against FCV, TuV and C. difficile.

Conclusion: Disinfectants containing H O are the most efficacious disinfection products against FCV, TuV and C. difficile endospores. Product formulation, rather than the concentration of H O in a product, impacts the efficacy of a disinfection product.

Significance And Impact Of Study: H O -based disinfectants are efficacious against surrogate viruses for HuNoV and C. difficile endospores.