HCPH Sanitarian Practice Test 2026 - Free Sanitarian Exam Practice Questions and Study Guide

Thermophiles are best described as organisms that thrive at high temperatures, specifically above 130°F (54°C). These microorganisms are adapted to live in extreme heat conditions, often found in environments such as hot springs, compost piles, and other hot environments where temperatures can exceed 60°C (140°F). Their adaptations allow them to maintain cellular structures and metabolic functions at these elevated temperatures.

The other definitions provided do not accurately represent thermophiles. For instance, microorganisms that thrive in cold environments would be classified as psychrophiles, while parasites found on plants do not pertain to thermophiles but rather describe a different biological group altogether. Mesophilic organisms are those that prefer moderate temperatures, typically between 20°C and 45°C (68°F and 113°F), which is distinct from the high-temperature preference of thermophiles. Thus, the definition that identifies thermophiles as organisms that cause off flavoring and grow best above 130°F captures their essence accurately.