Six different formulations were prepared, using different carrier materials namely; peat moss, mixture of peat moss plus vermiculite 1:2 (w/w), wheat bran, rice husk, clay and sodium alginate. Each carrier material was packed using polyethylene pages, and then divided into three groups. The first group was sterilized by autoclaving at 121?C for 20 min, the second one was sterilized by gamma irradiation at a dose rate of 4.0 kGy for 1 hour. However the third group was left without sterilization. Half of the inoculated polyethylene bags, containing the tested formulations either sterilized by autoclaving or gamma irradiation, were stored at 8?C and the other half of bags were stored at 30?C for 6 months. The non sterilized bags were stored under the same conditions but only for 3 months. For testing the survival of the strains, samples of the prepared formulations were taken every month during the storage period. Results revealed that non sterile formulations exerted high numbers of total fungi and bacteria along the storage period; however densities of the strains under investigation were decreased during the storage period.