Berachot without belief

Hi,

A berachah is invalid if it is recited by someone who rejects the existence of Gd or the validity of Torah. Therefore, his berachah on food, for example, could not fulfill the obligation of a listener.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 2:50)

Have a great day,
Mordechai