Thought you would appreciate this. If you have any additional Maareh Mekomos, please share with me. The Chida in the Nachal Kidumim brings a Birkas ha'Zevach who wonders how people ate Al Taharas ha'Kodesh all the time. Wouldn't they be Tevul Yom if they ever lived with their wives. That should prohibit them to eat Chulin if it is Al Taharas ha'Kodesh!
See attached copy of what he writes about this (available online at www.dafyomi.co.il/chagigah/discuss/chag018.qa5.pdf )
Yosey Goldstein, Baltimore USA
I don't really understand the question. If Chulin is eaten Al Taharas ha'Kodesh, it doesn't make the Chulin into Kodesh. Rather, the person acts with the Chulin as he normally would with Kodesh. He refrains from eating it if it was touched by a Tevul Yom, just like he would refrain from eating Kodesh touched by a Tevul Yom. But if he has reason to eat it, it is permitted to him.
When a person is Tamei, he has no obligation to starve. A Tamei Mes does not have to wait eight days to eat, if he normally eats Chulin Al Taharas ha'Kodesh. Rather, he simply does not practice the Chumra of Al Taharas ha'Kodesh during the days when he is Tamei. Therefore, even a Tevul Yom who normally eats Al Taharas ha'Kodesh can enjoy his Se'udas Shabbos b'Tum'ah.
Best wishes,
Mordecai Kornfeld
Kollel Iyun Hadaf