Sahih Muslim Book 3, Hadith Number 728.

Chapter : It is permissible to eat without ablution and there is no abhorrence in it and performing of ablution immediately (after that) is not essential.

Ibn Abbas, reported: The Apostle of Allah (may peace be upon him) came out of the privy after relieving himself, and food was brought to him and he took it, and did not touch water. In another narration transmitted by Sa’id b. al-Huwairith it is like this: It was said to the Apostle of Allah (may peace be upon him) You have not performed ablution. He said: I do not intend to say prayer that I should perform ablution.