From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer establishes that commerce in Torah-forbidden foods is Biblically prohibited, against the Terumas HaDeshen, while adopting the Chavos Yair's distinction that items with a sha'as hakosher (nevelos, treifos) are only Rabbinically prohibited in commerce, whereas items never permitted (shekatzim, remasim) are Biblically prohibited. He resolves the Tosfos Yom Tov's difficulty from Bechoros by showing that tziyr of eiver min hachai is permitted for Bnei Noach, making cheese commerce viable, and brings structural proof from the Rambam's organization in Mishneh Torah to support the Chavos Yair's distinction.
Source: Shu"t Chasam Sofer YD §106