A technique for obtaining linear heat-survivor curves with Staphylococcus aureus and its application to the assay of sublethal heat injury.
Staphylococcus aureus was grown in a complex (HK) medium either by a batch technique or by a modified batch technique after growth in a chemostat. These cultures were heat-treated at 52 degrees C, and counted on trypticase soy agar (TSA) or trypticase soy agar containing 7.5% NaCl (TSAS). When linear heat-survivor curves were obtained decimal reduction times (D52 degrees C) could be calculated from the TSA counts and pseudodecimal reduction times (D' 52 degrees C) from the TSAS counts. The D or D' values of batch-grown cells varied from 22 to 133 min and from 3 to 12 min, respectively. With cells grown by the modified technique the values were less variable (D was 22-51 min and D' was 3-7 min). D and D' values could be calculated from the same heat treatment in two of the six estimations with cells grown by the modified technique.
D001431:Bacteriological Techniques; D002452:Cell Count; D006358:Hot Temperature; D008954:Models, Biological; D013211:Staphylococcus aureus / Q000254:growth & development*