Statistical calibration of microbial suspensions in carrier controls during a textile disinfection ring trial

Abstract

IntroductionThe high number of uncontrollable variables in microbiological systems increases experimental complexity and reduces accuracy, potentially leading to data misinterpretation or uncorrectable errors. During an interlaboratory calibration analysis it was observed that the microbial logarithmic reduction (LR) caused by disinfectants depends not only on the type of disinfectant but also on the initial microbial load in the fabric carriers, which can produce a misinterpretation of the results. Fabric carriers are commonly used in standard tests such as EN16616 and ASTM2274. ObjectiveA method based on statistical calibration is proposed using a regression line between N0 (initial microbial load in the carrier) and LR to eliminate the influence of one on the other. ResultsAn example with Candida albicans is presented. Once the method was applied, the influence of N0 on LR was eliminated and the new LR values can be used for factorial experiments, for example, to check the efficacy of disinfectants or detergents without depending on the microbial load placed in the carrier.