I can't remember where I saw the following in Eruvin: Trying to find the Gemora in Eruvin that says that a specific case of Tevel is referring to a situation that they had exactly one kezayos and they could not take off terumos/maaser
Where was that Gemora...(it is in the first half of Eruvin)
Thanks
Good Shabbos
Bernard, new york
Shalom and thanks for your question. I think you are referring to Gemara on Daf 30b, which suggests a case where the entire Eiruv was exactly the size of two meals, thus if he would separate T'rumos/Ma'asros, there would not be enough Chulin remaining for the Eiruv. (The Gemora quickly rejects this possibility.)
Kol tuv.
Yehuda Landy