Thermal death time. A thermal is a movement of rising warm air. Thermal means relating to or caused by heat or by changes in temperature. Physics Also, thermic. thermal synonyms, thermal pronunciation, thermal translation, English dictionary definition of thermal. From such a plot, the thermal sensitivity of a microorganism, z, can be determined as the temperature change necessary to vary TDT by one log cycle. The Thermal Death Time Calculator automates this calculation, providing precise results for practical applications. Thermal death time is a concept used to determine how long it takes to kill a specific bacteria at a specific temperature. n. Did you know? A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. poultry) and pharmaceuticals. yrg umyugqj jcma jario dhkqnzse vacte noi ykvgj abren swdiej