Supplementing animal food with bacteriophages active against animal bacterial pathogens can be an excellent way of mildly influencing the quality of food and the health condition of animal breeding. Polysaccharides were used to immobilize biologically active cultures, and the technique of low-temperature drying under atmospheric pressure was chosen to maintain microbiological activity. Periodically dried material had the form of spheres with initial diameter 3 mm and moisture content 97%. The average initial concentration of bacteriophages of Siphoviridae family was 1×10 8 PFU/g (plaque-forming units per gram). Drying tests were carried out in temperatures range from -10°C up to 30°C. The activity of bacteriophages was checked prior and after drying, by enumeration by double agar overlay plaque assay.