What is plankton's middle name?

In the episode, "Plankton's Army" Plankton announced his full name once he got to the secret formula. He said, "I, Sheldon Jay Plankton," So his middle name must be "Jay".

However, if you look at the transcript for the epison, Plankton says, "Sheldon J. Plankton." Therefore, his middle name is not mention, but his middle initial is "J."