For spices: Pesachim 44a
Status where Terumah fell from 2 spice-mortars into 2 containers of Regular Produce: Pesachim 44a
Status where rodents took from 2 boxes, one of Modern Terumah and one of Regular Produce, and put them into 2 boxes: Pesachim 9b-10a, 44a
Assuming Terumah was separated from a Trusted Person's produce: Pesachim 4b, 9a
