Blast chillers rapidly cool food by circulating cold air through the unit until temperatures fall to safe levels. They are designed to lower the temperature of cooked foods quickly enough to minimize bacterial growth, ensuring the food is out of the 40 to 140 degree Fahrenheit danger zone within 90 minutes, rather than the hours it can take when foods are stored in a refrigerator.
Bacteria thrives between the temperatures of 40 and 140 degrees Fahrenheit. The longer food stays within this range, the greater the risk of bacterial growth that makes the food dangerous to eat. A conventional refrigeration unit may take too long to cool a large volume of hot food, and the heat from the food may also raise the ambient temperature of the refrigerator high enough to encourage bacterial growth in other items stored inside the unit.
Blast chillers are also suitable for freezing food and offer some advantages over a traditional freezer unit. Rapid freezing produces fewer and smaller ice crystals in food, which results in less damage to the food item due to perforated cell walls. This improves the texture of quick-frozen food once it is reheated. More expensive than refrigerators, blast chillers are typically used in food service and restaurants rather than home kitchens.