Final answer:
The person who washes hands and changes gloves after prepping hamburgers and before chopping lettuce is best described as a food preparer, demonstrating good food safety practices.
Step-by-step explanation:
The individual in the provided scenario who washes hands and changes gloves after prepping hamburgers and before chopping lettuce is fulfilling tasks that are typically associated with the role of a food preparer. This behavior of maintaining cleanliness and preventing cross-contamination is essential for food safety and is in line with the best practices recommended by health authorities. By changing gloves and washing hands between handling different types of food, the food preparer is taking an important step to prevent the spread of foodborne diseases.