PT  - JOURNAL ARTICLE
AU  - Vessoni Penna, Thereza Christina
AU  - Machoshvili, Irene Alexeevna
AU  - Santos Taqueda, Maria Elena
TI  - Thermal Resistance of Bacillus stearothermophilus Spores on Strips Previously Treated with Calcium
DP  - 1996 Jul 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 227--237
VI  - 50
IP  - 4
4099  - http://journal.pda.org/content/50/4/227.short
4100  - http://journal.pda.org/content/50/4/227.full
SO  - PDA J Pharm Sci Technol1996 Jul 01; 50
AB  - Moist thermal resistance parameters of spores of B. stearothermophilus ATCC 7953, inoculated in aqueous suspensions and on strips, were evaluated at 118°C and 121°C, by the proposed serum-bottle-mini-autoclave method. The present work studied the effect of alkaline calcium exchange-inducing storage treatments on the viability and moist heat-resistance of B. stearothermophilus spores, stored at – 18°C, following impregnation into filter paper strips which had been previously treated by immersion in alkaline 0.02 M calcium acetate. The thermal resistance of B. stearothermophilus spores on strip at set work conditions as biological indicator exhibited an average medium D (121°C) of 1.92 min for concentrations of 105–106 spores per strip over 360 days of storage in a freezer. The serum-bottle-mini-autoclave measuring system resulted in reasonably accurate and reproducible Bls calibration, before using them in an equipment validation program. The calcium acetate-strip system demonstrated a very high stability (Ea = 49.95 kcal/mol) to keep the spore viability and thermoresistance over steam cycles and storage. The heat activation kinetics of spores were also studied.