How can refrigeration prevent the growth of bacteria?

Refrigeration effectively prevents the growth of bacteria primarily by slowing down bacterial metabolism and reproduction. When food is stored at low temperatures, the biochemical processes that bacteria rely on for growth are significantly hindered. Most bacteria thrive in warmer environments, typically between 40°F and 140°F (4°C and 60°C), known as the danger zone. By keeping food refrigerated, usually at or below 40°F (4°C), the growth rate of bacteria is dramatically reduced, which helps to prolong the shelf life of food and reduce the risk of foodborne illnesses.

The other options do not directly relate to how refrigeration influences bacterial growth. Heating food before serving is a method that kills bacteria but does not prevent their growth in stored food. Maintaining a steady cooking temperature addresses the cooking process but does not apply to refrigeration. Increasing humidity in the storage area may actually promote bacterial growth, as many bacteria thrive in moist environments. Thus, refrigeration's primary role in food safety is its ability to inhibit bacterial activity through reduced temperatures.