Reference for Zevachim 145:1
כל דבר שיש בו מנין אפילו בדרבנן לא בטיל וכל שכן בדאורייתא
<br> Whatsoever is numbered [in selling], even [if its prohibition is] Rabbinical, cannot be neutralized, and how much the more when it is Biblical! For it was taught: If a litra of dried figs was pressed on the top of a round jar, and he does not know in which jar it was pressed; or on the top of a cask, and he does not know in which cask; or on top of a 'beehive', and he does not know in which, R. Meir maintains that R. Eliezer said: We regard the upper [layers] as if they are separated, and the lower ones neutralize the upper ones; while R. Joshua ruled: If there were a hundred tops, they neutralize; if not, [all] the tops are forbidden, and the bottom layers are permitted. R. Judah maintained: R. Eliezer said: If there were a hundred tops, they neutralize; if not, [all] the tops are forbidden etc.; while R. Joshua ruled: Even if you have three hundred tops, they do not neutralize. If he pressed it in a round jar, and he does not know in which part of the jar he pressed it, whether in the north or in the south, all agree that it is neutralized. R. Ashi said: You may even say [that it agrees with] the Rabbis: Living creatures are important, and cannot be neutralized.