PT  - JOURNAL ARTICLE
AU  - Thereza Christina Vessoni Penna
AU  - Irene A. Machoshvili
AU  - Maria Elena Santos Taqueda
AU  - Marina Ishii
TI  - The Effect of Media Composition on the Thermal Resistance of <em>Bacillus stearothermophilus</em>
DP  - 2000 Sep 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 398--412
VI  - 54
IP  - 5
4099  - http://journal.pda.org/content/54/5/398.short
4100  - http://journal.pda.org/content/54/5/398.full
SO  - PDA J Pharm Sci Technol2000 Sep 01; 54
AB  - Spores of Bacillus stearothermophilus ATCC 7953 were developed at 62° C on 32 media composed of various amounts of 11 components: D-glucose, L-glutamic acid, yeast extract, peptone, sodium chloride, magnesium sulfate, ammonium phosphate, potassium phosphate, calcium chloride, ferrous sulfate and manganese sulfate. Statistical models were used and demonstrated a strong interaction of yeast/peptone/ammonium phosphate, contributing positively to the best sporulation yield (6–7 log10 spores). The most influential medium components on the thermal resistance (at 121° C) of spores in suspension (calcium acetate, pH 9.7) were yeast extract (positively) and potassium phosphate (negatively), both creating the positive interaction, for spores from a 6-day incubation period. However, the strong negative effect of sodium chloride decreased the D-value from 1.81 min to 0.57 min upon increasing the incubation period (62° C) from 3 days to 6 days. The D-glucose and peptone exhibited greater effects than the yeast extract and potassium phosphate interaction on Dvalues for 3-day spores on strip, just as the highly joint-positive peptone/sodium chloride effect maintained the thermal resistance of 6-day spores on strips. The spores on strip system showed less stability than the spores in suspension. The most stable spore system confirmed D-values at 121° C at a range between 1.5 min and 1.9 min, which were obtained by keeping sodium chloride and potassium phosphate at minimum concentrations and yeast extract and peptone at maximum concentrations, regardless of the 3- to 6-day sporulation.