Biological formulations have evolved from the use of organic based solids such as peat as a preservative and delivery system to water based carriers. Water based formulations provide more convenience for the end user. Innovations in media preparation, stabilizing agents and packaging have led to stable formulations of non-spore forming microorganisms.

Liquid media for biological formulations contain either minimal nutrient levels packaged in air impermeable containers, or very high nutrient levels packaged in oxygen permeable plastic. Soluble polysaccharides (particularly alginates) can be used as stabilizing agents. Also, concentrated pastes of cells which are kept frozen until use, lyophilized powders, and oil suspensions are available. Two important points for the successful liquid formulation of a biological are long term stability (1 to 2 years) and effectivity at the site of use.