It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that he said: "The Messenger of Allah (peace and blessings be upon him) would eat tharid (bread soaked in meat broth) and drink milk, and then he (peace and blessings be upon him) would pray without performing (a new) ablution."
This hadith establishes juristically that consuming things cooked on fire, or milk, does not invalidate ablution, and this practice of his (peace and blessings be upon him) is based on teaching the Ummah permissibility and ease. As for its chain, this narration is found in various books of hadith, and one of its narrators, Abd al-A'la bin Amir al-Tha'labi, although saduq (truthful), has been criticised by the hadith scholars regarding his memory; but on the basis of other supporting reports, the basic ruling that something cooked on fire does not break ablution is established and firm.
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الطهارة / 153
Hadith Gradingمحدثین:إسناده ضعيف
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده ضعيف. » «أخرجه الضياء المقدسي فى "الأحاديث المختارة"، 730، والبيهقي فى«سننه الكبير» برقم: 748، وأبو يعلى فى «مسنده» برقم: 512، وأورده ابن حجر فى "المطالب العالية"، 153، وأخرجه عبد الرزاق فى «مصنفه» برقم: 641»