Yosef Karo, Shulchan Aruch — Yoreh Deah 322
“ Also, if the dough becomes impure by mistake or by compulsion, even the householder separates 1:48. Seif 2: One is not obligated [to take] challah from the Torah except in Israel, as it says, “and you eat of the bread of the land,” and at the time when all Israel was there, as it says, “in your coming,” – the coming of all of you, and not some of you. ”
