Final answer:
The soup must be reheated to a temperature of 165°F (74°C) for 15 seconds.
Step-by-step explanation:
The soup must be reheated to a temperature of 165°F (74°C) for 15 seconds.
According to food safety guidelines, perishable foods should be held at or above 140°F (60°C) to prevent bacterial growth. If the temperature of the soup dropped to 130°F (54°C) within 2 hours of hot holding, it is no longer safe to serve. The soup needs to be reheated to a temperature of 165°F (74°C) to ensure any potential bacteria are killed.