Musnad Abu Ya'la al-Mawsili 150:98

Ahmad ibn Mani' narrated to us, Marwan narrated to us, from Razin al-Bakri, who said: A freedwoman of ours, who is called Salma from Bakr ibn Wa'il, narrated to us that she heard 'Aishah say: The Messenger of Allah (may Allah bless him and grant him peace) entered and said: "O 'Aishah, is there any piece of bread?" I brought him a loaf, and he placed it to his mouth and said: "O 'Aishah, has anything of it entered my stomach?" Likewise is the kissing of the fasting person; breaking the fast is only from what enters, and not from what exits.