Bitul Issur L'chatchilah (Bitul and Blios #33 - Shulchan Aruch YD 99:5-6)
Rabbi Dovid Cohen
Bitul Issur L'chatchilah Which foods - heter, rennet, maris ayin, safek, ingredient; Non-food issues - puree, pegimah, remove issur, aino ben yomo; Which people - manufacturer, hashgachah, choice, machmir; Ain kavonoso levatel - classic, k'derech hamichabdim, shefah, airborne. See seforim by Rabbi Cohen at www.kashrushalacha.com