Based on the foregoing, we can answer that Rashi holds that terumah is eaten by the kohanim משלחן גבוה from that table from upon high. They are not eating their own. Hence, the food is not ממשקה ישראל at all. It is Divine food, not people food.
Now, we were compelled to explain that according to Rashi terumah is משלחן גבוה in order to explain why kohanim may not eat tevel [because it is a mixture of tevel and terumah and forbidden until its separation]. But Tosfos follows a completely different line of thought. They say that tevel is an איסור עצמי - an independent prohibition. Based on this understanding they correctly asked - Why should מדומע be אסור? Terumah is מותר as is חולין and they don't subscribe to the notion of משלחן גבוה with respect to terumah. But according to Rashi, Tosfos' question is properly answered - terumah can't be considered ממשקה ישראל because it is not our own food but G-d's.
Geshmaaaaackkkk!!
Stay tuned for more bl"n!
