List three primary groups of microbes with respect to growth temperature. which group would constitute food spoilage risk and why?

Bacteria can be grouped based on the temperature on which their growth is favorable.

Thermophiles: A thermophile can be defined as an organism that can grow a high temperatures. The temperature ranges from 41 to 122 °C. They are found in hydro thermal vents  and are found to be oldest on earth.

Mesophiles: It can be defined as organism which best grows in the temperature that is neither hot nor cold. The temperature ranges in between 20 to 45 °C.

Psychrophiles: It can be defined as the organism that tend to survive in colder conditions which ranges in between −20 °C to +10 °C.

Most of bacteria that constitute in food spoilage are mesophiles because food is usually kept at room temperatures which favors its growth.