ATCC, a leading supplier of authenticated biological materials, is partnering with Biolog, Inc. to monitor phenotypic drift in bacterial strains as well as characterize WHO listed fungal pathogens. Understanding the phenotypic profile of a given microbe is key to contextualizing the results of any study. Here, we generated baseline phenotypic profiles for eleven fungal pathogens recognized by the WHO to be of special concern in the global health community and common production and research strains of bacteria. To investigate the occurrence of phenotypic drift in laboratory and production strains we then simulated years of passages while monitoring for changes in each organism’s phenotypic profile. Once phenotypic drift was captured, affected generations were then sequenced to ascertain the occurrence of mutations within each strain. This study demonstrated that high-throughput phenotypic screening is a valuable tool for characterizing strains and monitoring phenotypic instability due to genetic changes due to passaging, highlighting the importance of using authenticated strains and minimizing passaging for reliable bioproduction and experiment.