Microbial Cytometric Mock Community for use in flow cytometric analysis, the microbial Cytometric Mock Community comprising or consisting of cells of at least three different microbial species in a pre-defined ratio, wherein the at least three different microbial species are selected such that, when measured using flow cytometry, the specific gate pattern of each microbial species differs significantly from the specific gate pattern of the other microbial species of the microbial Cytometric Mock Community, preferably the at least three different microbial species differ in overall DNA content, relative genomic GC-content, average cell size, Gram +/− affiliation and/or capacity to form spores.