Which is an unsafe method for cooling large amounts of hot food?

Storing large amounts of hot food directly in a refrigerator is considered an unsafe method for cooling because it can lead to an increase in the temperature inside the refrigerator. When hot food is placed in a refrigerator, it raises the overall temperature of the fridge, potentially putting other stored foods at risk of entering the danger zone (between 41°F and 135°F), where bacteria can multiply rapidly.

In contrast, the other methods listed are effective cooling techniques. An ice-water bath allows heat to be removed quickly from the food surface, promoting rapid cooling. A blast chiller is designed to cool food quickly and evenly by rapidly circulating cold air around it. Using an ice paddle involves stirring the hot food while the paddle, which is filled with ice water, cools the mixture efficiently. Each of these methods helps ensure food remains out of the danger zone during cooling, minimizing the risk of foodborne illnesses.