Microcalorimetry applied to certain species of bacteria growing in sterilized separated milk

Abstract

Summary: The heat produced per colony-forming unit (CFU) of growing bacteria was found to depend on the species and was greater the younger the culture. With the exception of 2 determinations out of 13, with 6 species the results show that it should be possible to detect < 5×10⁵CFU/ml by the heat produced. A seventh species, a micrococcus, could be detected at a lower level of CFU presumably because the unit was a clump of several cells. Gross variations which occurred with fullcream milk await investigation.