Canning and Fish Packaging Technology

Unit 4 - Thermal process for canned foods

4.6.Time temperature relationship in bacterial destruction and “thermal death time” of bacteria
It has been found that the higher the lethal temperature of heating, the shorter is the time required to destroy any given number of bacteria or spores. D value gives a good representation of the proportion of number of cells killed in unit time during heating process but the effect of change in temperature of heating cannot ascertained. Therefore, to obtain the combined effect of time and temperature on destruction of bacteria/spore, thermal destruction curve or often referred as thermal death time curve is required.