Which method of cooling foods is not acceptable?

Covering tightly and placing food on the counter at room temperature is not an acceptable method for cooling foods because it can lead to unsafe temperature conditions that promote the growth of harmful bacteria. When food is allowed to cool slowly on the counter, it remains in the "danger zone" — a temperature range between 41°F and 135°F — for too long. In this zone, bacterial growth can occur rapidly, increasing the risk of foodborne illness.

In contrast, other methods listed are acceptable for cooling foods efficiently and safely. Using ice made from potable water helps to lower the temperature of food rapidly. Placing food in shallow pans allows for more surface area exposure to cooler air, which accelerates the cooling process. Stirring food can help distribute heat evenly, aiding in quicker cooling as well. Each of these methods works to ensure that food cools down to safe temperatures in a timely manner, thereby reducing the risk of bacterial growth and ensuring food safety.