Reference for Bekhorot 53:16

רב הונא בריה דרב יהושע כי מתרמי ליה חמרא דתרומה הוה רמי תרי נטלי דחולין וחדא נטלא דתרומה ושקיל חד

Samuel further said: Terumah from abroad one may go on eating, leaving the separation for afterwards.<span class="x" onmousemove="('comment',' Even delaying the separation until the end. According to Tosaf., however, there must remain a portion of the pile even after the separation, to carry out the principle of mukaf (lit., 'brought near') requiring that the terumah must be of a mass in close neighbourhood of the products from which it is set aside.');">¹³</span>

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