When bacterial populations are heated or treated with antimicrobial agents, they usually die at a constant rate. For example, suppose a population of 1 million microbes has been treated for one minute, and 90% of the population has died, we are now left with 100,000 microbes. Thus for every minute the treatment is applied 90% of the remaining population is killed. If the death curve is plotted logarithmically, the death rate is constant.
Factors that influence the effectiveness if antimicrobial agents:
1. The number of microbes
2. Environmental influences
3. Time of exposure
4. Microbial characteristics