Related Experiment Video
Updated: Jan 24, 2026

Author Spotlight: Exploring Heat Shock Proteins in Malaria and Tuberculosis Infections
Published on: March 8, 2024
Heat Shock, Anaerobic Jar Incubation and Fluid Thioglycollate Medium Have Contrasting Effects on D-values of
Theresa A Gadzella1, Steven C Ingham1
1Department of Applied Microbiology and Food Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWO.
Abstract:
This study investigated the effects of heat shock and post-heat environmental conditions on the survival of Escherichia coli ATCC 25922 at 52, 54 and 56°C. Significantly (P <0.05) higher decimal reduction time-values (D-values) in nutrient broth at all three temperatures were obtained when the cells had been previously heat shocked at 46°C for 1 h. This heat shock effect was greatest at 56°C, followed by 54 and 52°C. Anaerobic jar incubation of heat-stressed cells led to D-values higher than those obtained using aerobic incubation, but the difference was only statistically significant at 56°C. Previous studies showed that fluid thioglycollate medium and thioglycollic acid enhanced the recovery of heat-stressed Salmonella enteritidis and E. coli , respectively. However, a fluid thioglycollate medium overlay of spread plates significantly decreased the D-values of E. coli ATCC 25922 at 52, 54 and 56°C. When the fluid thioglycollate medium was used to overlay pour plates, no significant changes in D-values were seen.
Related Concept Videos
Biodiversity and Human Values
Professional Values
The values that are the foundation of the nursing profession are altruism, autonomy, human dignity, and social justice.
First, altruism refers to the concern for the welfare and well-being of others without personal...
Responses to Heat and Cold Stress
Critical Values
z Scores and Unusual Values
This score indicates how far a value is from the mean in terms of standard deviation. For example, if a data value has a z score of +1, the researcher can infer that the particular data value is one standard deviation above the mean. If another data...
Shock Waves
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high...

