The work "steht" in this particular joke

I recently read a joke in German....Eine Ärztin geht zum Essen. Sie bemerkt das der Kellner ständig seinen Kopf krazt. Sie fragt: “Haben Sie Juckreiz?”
Der Kellner antwortet: “Wenn es nicht auf der Speisekarte steht haben wir es nicht
 
The joke is ok I guess, afterall, humour is in the eye of the beholder right?. What I want to know is...what business is "steht" doing there in the last sentence?

That's an idiomatic usage in German.  We use stand more literally in English, but in German it is often used to mean in existence or there.

Great thanks Byron, that's cleared it up for me. That's the best answer I've had and I've posted it on another forum as well