THE EFFECT OF DIFFERENT WATER-INSOLUBLE ANORGANIC SALTS ON THE RESISTANCE AND STORAGE TIME OF BACILLUS-STEAROTHERMOPHILUS SPORES USED FOR BIOLOGICAL INDICATORS

The survival of Bacillus stearothermophilus spores was investigated ov er 7 years. The spores were precipitated with 18 unsoluble anorganic s alts. There were hydroxides, carbonates, oxalates, phosphates, and sul fate of aluminium, barium, calcium, iron, magnesium, manganese, and ti n. The stability of the spores to dry and moist heat was strongest in precipitates of barium and calcium salts. Most phosphates and the heav y metals caused a rapid inactivation of spores. Finally, the survival of the spores in the 7 years of observation was the best in bariumsulf ate and calciumoxalate.