Reference for Chullin 257:28

א"ל רב פפא לרבא הא דתניא

is not decreed by the law of the Torah; for should you say it is so by the law of the Torah then we should have a case of foodstuffs being able to convey the graver uncleanness!<span class="x" onmousemove="('comment',' And this cannot be for then it would not need to be made susceptible to uncleanness, in accordance with the rule quoted, supra 121a.');">¹⁷</span>

Jastrow

Jastrow