Reference for Beitzah 6:8

(א"ל) סיפא אתאן לספק טרפה

(They [Rav Yoseif and Rabbi Yitzhak] would say to you:) "The end [of the Mishnah, referring to the doubtful egg] refers to a case of a doubtful treyf [egg from a treyf bird, i.e. a Torahitic doubt]."

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