Final answer:
The HACCP principle being practiced when food handlers rewash melons that have surface dirt is Prerequisite Programs.
Step-by-step explanation:
When food handlers rewash melons that have surface dirt, they are practicing the HACCP principle of Prerequisite Programs. Prerequisite programs are the foundation of the HACCP system and include procedures that focus on good manufacturing practices, such as cleaning and sanitation, to prevent hazards from entering the food supply. By rewashing melons, the food handlers are ensuring that any surface dirt or contaminants are removed before the melons are consumed.