I think you're confusing episodes. In his first appearance he mentions that he's allergic to citrus. The "I love lemon chicken" incident comes from Carter's vis

I think you're confusing episodes. In his first appearance he mentions that he's allergic to citrus. The "I love lemon chicken" incident comes from Carter's visit to a parallel universe when she's experimenting with the merlin device in a later season. ...I'm really embarrassed that I know that from memory.