The ideal temperature range for bacterial growth varies among different groups of bacteria. The optimum temperature for most of the pathogenic bacteria is 37°C, which is the same as the human body. 

Based on ideal temperature for growth, bacteria may be categorized into the following groups: 

• Thermophiles: Heat-loving bacteria are called thermophiles. These bacteria can tolerate high temperatures and their ideal temperature range for growth is 55°C to 80°C.
• Mesophiles: Mesophiles include bacteria that thrive in moderate temperatures that range from 25°C to 40°C. Most pathogenic bacteria are mesophiles. 
• Psychrophiles: Psychrophiles are cold-loving microbes. They grow best at low temperatures ranges between 0°C and 20°C