Tajio looked up to his head chef but was frustrated by the fact that he hadn’t taught him how to cook. However, this relationship closely parallels Sanji and Zeff’s working relationship; as the head chef would instruct his line cooks, he was allowing Tajio to learn by listening as he cleaned dishes. Tajio was able to learn how to make a very good stew this way, which impressed a number of high-ranking Marine officials.

(Source: One Piece Wiki)