Final answer:
The correct action when the temperature of minestrone soup in a hot-holding unit is below the critical limit is to reheat the soup to 165 degrees F within 2 hours.
Step-by-step explanation:
When the temperature of minestrone soup in a hot-holding unit is below the critical limit, the correct action is to reheat the soup to 165 degrees F within 2 hours. This ensures that any harmful bacteria that may have multiplied due to the improper temperature are killed, making the soup safe to consume. It is important to follow proper food safety guidelines to prevent foodborne illnesses.