Abstract
This article outlines the procedure of microbial calorimetry and its application to food microbiology and soil microbiology. The process of putrefaction of food, which can be regarded as the growth of microbes in food, and the process of carbon-source assimilation by soil microbes can be observed by a calorimetric method. From the time course of the calorimetric signal, we can obtain several values, such as the time T1/2, at which half of the total heat evolution is completed, and the time M, at which the heat-evolution rate reaches its maximum value. By analyzing the dependencies of these parameters on a chemical concentration such as sodium chloride, several repressive parameters of the chemical can be evaluated: the concentration Ki, at which the specific putrefactive or assimilative activity is half repressed; the repressive cooperativity m; and the minimum inhibition concentration MIC. This calorimetric method has the advantages that it does not require highly specialized knowledge or skills in either food or soil microbiology and that it can detect the putrefactive and assimilative activities of both “viable but non-culturable” and culturable microbes.
https://ror.org/01529vy56 
