How many hours do foods need to cool from 20°C to 4°C?

The correct answer highlights important food safety practices that are crucial for preventing foodborne illnesses. According to guidelines set by health authorities, when cooling foods, they should be brought from 20°C to 4°C within a specific time frame to limit the growth of harmful bacteria.

The safe cooling process follows the two-stage cooling method, wherein the food must first cool from 60°C to 20°C within two hours, and then from 20°C to 4°C in an additional four hours. This ensures that food passes through the danger zone (between 4°C and 60°C, where bacteria grow rapidly) as quickly as possible.

By allowing a maximum of four hours for the temperature to drop from 20°C to 4°C, it helps to minimize the time that food is kept in an unsafe temperature range, further protecting public health. Thus, to correctly answer the question, foods need to cool from 20°C to 4°C in no more than four hours to ensure safety and adhere to established food safety guidelines.