Jami` at-Tirmidhi Book 26, Hadith 29
"The Messenger of Allah (ﷺ) prohibited breathing in the vessel, or blowing into it."
This Hadith is Hasan Sahih.
That the Prophet (ﷺ) prohibited blowing into the drink. A man said: "What about if one sees something floating in the vessel?" He said: "Spill it out (removing that)." He said: "I can not drink in one breath." He said: "Then remove the cup away from your mouth."
This Hadith is Hasan Sahih.
From his father, that the Messenger of Allah (ﷺ) said: "When one of you drinks, then do not breathe into the vessel."
This Hadith is Hasan Sahih.