Reference for Chullin 257:30

טומאתו אגב כוליא לאו דאורייתא דאי סלקא דעתך דאורייתא מצינו לאוכל שמטמא טומאה חמורה

For it now serves as wood.<span class="x" onmousemove="('comment',' The fat that encloses the kidney conveys uncleanness not by virtue of its being a foodstuff but, on the contrary, rather as a bone or wood which serves as a protection to the kidney which is nebelah. u,tnuy');">¹⁸</span>

Jastrow

Jastrow