Since cysts are hatched in shrimp hatcheries without sterile conditions, we liked to study quantitatively and qualitatively the TCBSB population from different Artemia brands, under laboratory sterile conditions, in order to establish the composition of normal bacterial population isolated on TCBS media, from Artemia cysts. We also compared the TCBSB population from larvae hatched from the same brand and the same lot with (laboratory) and without (hatchery) sterile conditions