What type of bacteria are commonly found in human bodies and food products?

Mesophilic bacteria are the correct answer because they thrive in moderate temperature ranges that are typically found in the human body and in many food products. These bacteria generally grow best at temperatures between 20°C and 45°C (68°F to 113°F), which aligns well with the human body temperature (approximately 37°C or 98.6°F). This optimal growth temperature allows mesophilic bacteria to play significant roles in human health, digestion, and food spoilage, as they are commonly present in our gut flora and in various food fermentation processes.

In contrast, thermophilic bacteria thrive in high-temperature environments (above 45°C or 113°F) and are not commonly found in human bodies, but rather in hot springs and composting organic material. Psychrophilic bacteria are adapted to cold environments, typically growing at temperatures below 20°C (68°F), making them more prevalent in polar regions or refrigerated products, but not in the human body under normal conditions. Halophilic bacteria require high salinity environments, such as salt lakes or salt mines, and are not typically associated with the human body or standard food products.