refrigerate

Refrigerate is a verb meaning to chill a substance to temperatures below ambient, typically to slow the growth of microorganisms or chemical changes. The term comes from the Latin refrigerare, meaning to make cold again, and is used in everyday cooking, food safety, medicine, and storage contexts.

Refrigeration refers to maintaining a controlled cool temperature within a confined space or container. In households, refrigerators generally keep contents at about 2 to 4°C (35 to 40°F). The commonly cited safety guideline is to keep foods at or below 4°C, while freezers are kept near −18°C (0°F). The concept of the “danger zone” for food safety is 4–60°C (40–140°F), where bacteria multiply rapidly.

The mechanism in modern equipment is a closed vapor-compression cycle using a refrigerant fluid that absorbs heat from inside the cabinet as it evaporates and releases it outside as it condenses. Domestic units may be upright or chest models and may use different refrigerants. Advances focus on efficiency and reducing environmental impact of refrigerants.

History: before mechanical refrigeration, iceboxes used harvested ice. Mechanical refrigeration emerged in the 19th century and spread in the 20th, transforming food preservation, medical storage, and industrial processes by enabling longer shelf life and safer distribution.

Food safety and storage practices emphasize prompt refrigeration of perishable items, keeping containers shallow for rapid cooling, and avoiding the danger zone of 4–60°C (40–140°F). Some foods tolerate storage at room temperature; others require refrigeration to maintain texture, flavor, or safety.

Refrigeration also supports medicine storage, vaccines, and controlled climates for research and industry, while its use raises concerns about energy use and environmental impact of refrigerants.