The biologic standard used to test the efficiency of sterilization involves the use of
Spores of Clostridium tetani
Streptococcus pneumoniae
Spores of Vibrio
Mycoplamsa
Spores of Clostridium tetani is used for Dry Heat; 106 spores are used.For moist heat, Bacillus stearothermophilus are usedReference: Ananthanarayan and Paniker&;s Textbook of Microbiology; 10th edition
general microbiology