Methods for selecting a microbe for co-formulation with a carrier are provided. In some examples, the methods include identifying a microbe that comprises one or more dipicolinic acid (DPA) synthase genes, a microbe that expresses one or more DPA synthase proteins, and/or a microbe that produces DPA; and selecting the microbe for co-formulation with a carrier. The methods optionally include co-formulating the selected microbe with the carrier. In some examples, the methods include detecting one or more DPA synthase genes or one or more DpaA and/or DpaB proteins in a microbe. In other examples, the methods include detecting DPA in a microbe or medium containing a microbe, for example, utilizing a fluorescence assay. Microbial compositions including one or more microbes that comprise one or more DPA synthase genes, express one or more DPA synthase proteins and/or produce DPA are also provided.