@article{mbs:/content/journal/micro/10.1099/00221287-132-4-939, author = "Miles, Christopher A. and Mackey, Bernard M. and Parsons, Susan E.", title = "Differential Scanning Calorimetry of Bacteria", journal= "Microbiology", year = "1986", volume = "132", number = "4", pages = "939-952", doi = "https://doi.org/10.1099/00221287-132-4-939", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-132-4-939", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10°C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68–73, 77–84, 89–99 and 105–110°C respectively. Exceptions were that peak m (the largest peak) occurred at 79–82°C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119°C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5°C and re-heated, a small endothermic peak, pr , was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.", }