Shaykh Muqbil al-Wadi’i explains that if food is already in your mouth when the Athan is called, you should not spit it out, but you must not eat anything else afterward. Drinking is allowed only if the water is still in your hand when the Athan begins.
If a person is having Suhūr and the Athān is called. Is it obligatory upon him to spit out what is in his mouth or should he eat it?
That which is in his mouth then he should not spit it out, but nothing should be eaten that isn’t in his mouth after [the athān].
Except for water, for it has been reported in the Sunan of Abū Dāwūd by way of Abū, Hurayrah that the Messenger of Allāh ﷺ said: “If one of you hears the call (to prayer) and the vessel is still in his hand, let him not put it down until he fulfilled his needs with it.” So there is no problem in drinking if the Muathin has called the Athān with the condition that the water [utensil] is in his hand.
