Abu Dawud
Foods
Book Number: 021 / Hadith Number: 3758
Narated By 'Aisha, Ummul Mu'minin : The Apostle of Allah (pbuh) said: When one of you eats, he should mention Allah's name; if he forgets to mention Allah's name at the beginning, he should say: "In the name of Allah at the beginning and at the end of it."