3,378. Eating Tevel

Hilchos Maaser 1:5

If someone eats from his produce while it’s still untithed (tevel), or if a Levi eats maaser before terumas maaser has been taken, they are not obligated to pay the rightful recipients of those gifts even though they are liable to the penalty of death from Heaven. This is because Numbers 18:24 teaches “they will separate to God”; the kohanim and Leviim have no share in tithes until they have been separated. Outside of Israel, one may keep eating and take terumah and maaser later.

Hilchos Maaser 1:6

One may take maaser from produce in one location for produce in another location, but not from one type of produce for another, nor from produce that is obligated in maaser for produce that is exempt from maaser, nor vice versa. If one took tithes in any of those ways, the produce isn’t considered tithed.