18 Nov

Temperature and Bacterial Growth

There is a direct correlation between temperature and bacterial growth. Bacteria can grow over a wide range of temperatures that spans from 0 degrees C. and 100 degrees C. They can be divided into four groups based on their temperature requirements. Psychrophiles grow between -5 degrees C. and 20 degrees C. These bacteria can be found in the supercooled waters of the arctic and Antarctic. Mesophiles grow between 20 degrees C. and 50 degrees C. Most bacteria fall into this class which includes pathogens that grow between 35 degrees C. and 40 degrees C. Thermophiles grow between 50 degrees C. and 80 degrees C. Bacteria in this group grown in the soil where midday temperatures exceed 50 C. or in compost piles where fermentation causes the temperature to rise above 60 degrees C. Hyperthermophiles grow above 80 degrees C. These organisms grow where water has been heated by volcanic activity and the temperature has reached over 100 degrees C. Scientists have isolated these organisms from thermal vents deep within the ocean floor and from volcanic hot springs. One organism cannot grow over the entire range of temperatures. The temperature affects metabolic activity as well as other biochemical reactions.