Yoma 8:2-3

Yoma 8:2

If on Yom Kippur one eats a volume of food the size of a large date including the pit, or if he drinks a mouthful of liquid, he is liable. All kinds of food combine to form the volume of a date and all liquids combine to the volume of a mouthful. However, food and drink do not combine with one another.

Yoma 8:3

If a person both ate and drank in the same state of unawareness, he is only liable to bring one sin offering. If he both ate and performed an act of labor, he is liable for two sin offerings. If he ate or drank something that was not fit for consumption, or if he drank the brine from pickled food or fish, he is exempt.