Midrash su Levitico 22:6

5) (Vayikra 22:6) ("The soul that touches it shall be unclean until the evening; and he shall not eat of the holy things until he bathes his flesh in water.") "The soul that touches it": and not one (that becomes unclean) by moving it. "The soul that touches it shall be unclean until the evening; and he shall not eat of the holy things.": There are holy things of which he may not eat, to include intermixtures of less than a hundred.

6) This tells me only of an intermixture of foods of terumah with foods of terumah, (i.e., that a Cohein may not eat a sa'ah of unclean terumah that became intermixed with less than a hundred sa'ah of clean terumah.) Whence do I derive the same for an intermixture of foods of terumah with foods of chullin (non-terumah), foods of chullin with foods of terumah, foods of terumah with sanctified foods, sanctified foods with foods of terumah, terumah drink with chullin drink, chullin drink with terumah drink, terumah drink with sanctified drink, sanctified drink with terumah drink, sanctified drink with (another kind of) sanctified drink? To this end it is written "of the holy things," to include (all of the above).

7) "until he bathes his flesh": I might think that he could bathe each limb individually; it is, therefore, written (Vayikra 22 verse 7) "And when the sun sets he shall be clean" — Just as the sun sets as a whole, so the bathing in water must be as a whole (and not limb by limb).