In this work, motivated by the biology of microorganisms, it is reasonably explained, using mathematical language, that the maximun number of activated spores A(t) is given when in a given time t, the proportion of activated spores from an initial number of nonactivated ones is greater than the proportion of death spores from an initial number of those activated. This phenomenon is observed in the extrapolation of an exponential portion in the thermal death curve to a point in excess of the initial number of living spores reported by several microbiologist investigators for certain strain for bacterial spores, e.g., Bacillus stearothermophilus.