What is the required method for adding mayo to a sandwich?

Using the mayo scoop is the proper method for adding mayo to a sandwich because it ensures a consistent amount of mayo is applied to each sandwich. This method promotes cleanliness and hygiene, as it prevents direct contact with the mayo, reducing the risk of contamination and maintaining the quality of the product. Additionally, using a scoop allows for more control over the amount of mayo being added, which is important in achieving the desired flavor balance on the sandwich. This method aligns with standard practices in food preparation, emphasizing efficiency and sanitation in food service.