| Reference | [1]. Tung, G., Macinga, D., Arbogast, J. and Jaykus, L.A., 2013.<br />
Efficacy of commonly used disinfectants for inactivation of human noroviruses and their surrogates.<br />
Abstract: Human noroviruses (HuNoVs) are the most common cause of acute viral gastroenteritis worldwide and are a leading cause of foodborne disease. Their environmental persistence and purported resistance to disinfection undoubtedly contribute to their success as foodborne disease agents. The purpose of this study was to compare the efficacy of three commonly used disinfectant active ingredients against representative HuNoV strains and cultivable surrogates. Ethanol (50, 70, and 90%), sodium hypochlorite (5, 75, 250, 500, and 1,000 ppm), and a quaternary ammonium compound blend (at 0.1×, 1.0×, and 10× concentrations) were evaluated against two norovirus (NoV) genogroup II strains (GII.2 and GII.4) and two surrogates (feline calicivirus [FCV] and murine norovirus [MNV-1]). Virucidal suspension assays (30-s exposure) were conducted in accordance with ASTM International standard E-1052. Virus inactivation was quantified using reverse transcription quantitative PCR targeting the ORFI-ORFII junction (HuNoV), the RNA polymerase region (MNV-1), or the ORFI region (FCV); infectivity assays were also performed for MNV-1 and FCV. The two HuNoV strains and FCV were relatively resistant to ethanol (<0.5 log inactivation) irrespective of concentration, but MNV-1 was much more susceptible (log inactivation, ~2.0 log at higher ethanol concentrations). Both HuNoV strains were more resistant to hypochlorite than were either of the animal surrogates, with the human strains requiring ≥500 ppm of hypochlorite to achieve statistically significant reduction (≥3.0 log) in virus concentration. All four viruses were resistant to inactivation (<0.5-log reduction) using the quaternary ammonium compound formulation at all concentrations tested. This study is novel in that it clearly demonstrates the relative ineffectiveness of common active disinfectant ingredients against HuNoV and highlights the fact that the cultivable surrogates do not always mimic HuNoV strains.<br />
Journal of food protection, 76(7), pp.1210-1217.<br />
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[2]. Gerba, C.P., 2015.<br />
Quaternary ammonium biocides: efficacy in application.<br />
ABSTRACT: Quaternary ammonium compounds (QACs) are among the most commonly used disinfectants. There has been concern that their widespread use will lead to the development of resistant organisms, and it has been suggested that limits should be place on their use. While increases in tolerance to QACs have been observed, there is no clear evidence to support the development of resistance to QACs. Since efflux pumps are believe to account for at least some of the increased tolerance found in bacteria, there has been concern that this will enhance the resistance of bacteria to certain antibiotics. QACs are membrane-active agents interacting with the cytoplasmic membrane of bacteria and lipids of viruses. The wide variety of chemical structures possible has seen an evolution in their effectiveness and expansion of applications over the last century, including non-lipid-containing viruses (i.e., noroviruses). Selection of formulations and methods of application have been shown to affect the efficacy of QACs. While numerous laboratory studies on the efficacy of QACs are available, relatively few studies have been conducted to assess their efficacy in practice. Better standardized tests for assessing and defining the differences between increases in tolerance versus resistance are needed. The ecological dynamics of microbial communities where QACs are a main line of defense against exposure to pathogens need to be better understood in terms of sublethal doses and antibiotic resistance.<br />
Applied and environmental microbiology, 81(2), pp.464-469.
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