Final answer:
Food must reach a minimum temperature of 165°F before being placed in a hot holding unit to prevent foodborne diseases.
Step-by-step explanation:
The minimum temperature that food must reach before being placed in a hot holding unit is 165°F.
This guideline is set to ensure that food reaches a high enough temperature to kill any potential bacteria it may contain, thus preventing foodborne disease.
The danger zone for bacterial growth in perishable foods is between 40°F and 140°F, and such foods should not be left at these temperatures for more than two hours. As for hot holding units, the food should be kept hot until served to maintain food safety and quality.