I'd like to know, if your ice cream makers are NSF approved?

No, the makers are not yet NSF approved.

I am sorry for a stupid questions, but what is NSF?

\r\n\r\nNational Science Foundation\r\nan independent U.S. Government agency established in 1950, with a mission "To promote the progress of science; to advance the national health, prosperity, and welfare; and to secure the national defense."\r\n\r\n\r\na good place to find the meanings of words\r\nhttp://dast.nlanr.net/Glossary.html#N