Terumos 8:2-3

Terumos 8:2

Regarding the people in the previous mishna (who lost the right to eat terumah while in the act of eating terumah), Rabbi Eliezer permits them to swallow what’s in their mouths when they become informed, while Rabbi Yehoshua requires them to spit it out. If a kohein was eating terumah when he was informed that either he or the terumah has become ritually unclean (while he was eating it), Rabbi Eliezer permits him to swallow it, while Rabbi Yehoshua requires him to spit it out. If he was informed that he or the terumah was already ritually unclean (before he started eating it), or that it was tevel (untithed produce), first tithe from which terumah was not yet taken, or second tithe or sanctified produce that had not been redeemed, or if he tasted an insect in his mouth – in all of these cases, he must spit out what is in his mouth.

Terumos 8:3

(Necessary background information: A landowner may eat some untithed produce in the field but not in the house; the courtyard of a house likewise obligates the produce in tithes. The arrival of Shabbos also obligates produce in tithes.)

If a landowner was eating some grapes in his vineyard and, while doing so, he entered his courtyard, Rabbi Eliezer permits him to finish the cluster but Rabbi Yehoshua prohibits it. If he was eating it late on Friday afternoon and it became Shabbos, Rabbi Eliezer permits him to finish it but Rabbi Yehoshua prohibits it.