Ibrahim bin Abdullah (may Allah have mercy on him) says that once I saw Hazrat Abu Hurairah (may Allah be pleased with him) eating pieces of cheese and then starting to perform ablution. Seeing me, he said, "Do you know why I am performing ablution from something?" I had eaten some pieces of cheese, and I heard the Prophet Muhammad (peace and blessings be upon him) say, "Perform ablution after eating something cooked on fire."