Hazrat Abu Hurairah radiyallahu anha says that he once saw Rasoolullah sallallahu alaihe wasallam eat a piece of cheese then perform wudhu. Then he saw him at another time eat a shoulder of a goat, and perform salaah without performing wudhu. (ID)
English reference (ID): Book 25, Hadith 167 (ID)
Arabic reference (ID): Book 26, Hadith 176 (ID)