(21) Foods
كتاب الأطعمة
(6a) Chapter: Covering Vessels and other things - Section 1
(5) باب تغطية الأواني وغيرها - الفصل الأول
Mishkat al-Masabih 4299 
He told that when Abu Humaid, one of the Ansar, brought a vessel of milk to the Prophet from an-Naqi'* the Prophet said, “Why did you not cover it up, even by putting a piece of wood on it?” *A place in the wadi al-'Aqiq where camels which had been given in sadaqa were kept. (Bukhari and Muslim.)
وَعَنْهُ قَالَ: جَاءَ أَبُو حُمَيْدٍ رَجُلٌ مِنَ الْأَنْصَارِ مِنَ النَّقِيعِ بِإِنَاءٍ مِنْ لَبَنٍ إِلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أَلَّا خَمَّرْتَهُ وَلَوْ أنْ تعرِضَ عليهِ عوداً»
 مُتَّفق عَلَيْهِ  (الألباني)حكم :
Reference : Mishkat al-Masabih 4299
In-book reference : Book 21, Hadith 131