Hullin 120: When Food Is Not Food

When do spices join together with the meat to yield an amount that can impart impurity of food -- even though the spices alone wouldn't get that impurity to begin with, because spices aren't quite food for this purpose. The Gemara clarifies that it really means the scrapings - including meat - at the bottom of the pot. But what if that includes forbidden fats or coagulated blood or the like? Also, liquids that come from foods with special halakhic statuses -- and how those liquids have the special statuses as well.