Final answer:
Bacterial multiplication is rapid above 20 degrees C, particularly for mesophilic bacteria, which thrive between 20-40°C. Higher temperatures foster the growth of thermophiles and hyperthermophiles, which have higher optimal growth temperatures and do not multiply at room temperature like mesophiles.
Step-by-step explanation:
Above 20 degrees C, bacterial multiplication is rapid for mesophilic bacteria, which are the ones commonly worked with in laboratories. These bacteria grow at temperatures between 20-40°C, with some preferring body temperature (37°C), while others grow best at room temperature (approximately 25°C). Foods contaminated with bacteria may become dangerous if the temperature allows the rapid multiplication of these microorganisms, which generally occurs most rapidly at temperatures between about 4 and 60 degrees C (40 and 140 degrees F).For organisms such as thermophiles, which are 'heat-loving' bacteria, the optimal growth temperature can range from 50°C to a maximum of 80°C, and they do not multiply at room temperature. At the higher end of the temperature scale are hyperthermophiles, growing optimally at temperatures from 80°C to over 100°C. These bacteria do not represent the common behavior of mesophiles in terms of rapid multiplication rates at moderate temperatures.