is one piece episode 319 filler?

Sanji is buying groceries in the company of Chimney and Gonbe. For lunch, they lead him to the small floating restaurant of a drunken old man.

He is asleep and not easily woken, so Sanji decides to prepare something himself. While he is cooking, the old man wakes up and immediately recognizes Sanji's way of handling the knife, for he knew Sanji's mentor, "Red-Leg" Zeff.

He insists that Sanji taste some of his cooking. Sanji is amazed by the flavor, but cannot figure out how the old man made it.

Intent on discovering the secret, he searches the city for seasonings that might have been used.