This type of impurity is considered 'tumah kalah' - light impurity - because of the relatively low level of impurity it can create and communicate: Keritot 20b
Food becomes impure via contact with something which is impure from contact with liquids, biblically or rabbinically: Pesachim 14a-b, 19b
Food which is inedible to humans: Pesachim 45b
Food which people eat in some places and not others: Keritot 21a-b
Food remains impure until it is destroyed beyond edibility for a dog: Pesachim 15b, 45b; Keritot 21a
A container combines all parts of korbanot, but not of terumah, within it, to become impure once one of them becomes impure: Pesachim 19a
Whether the above rule is rabbinic or biblical: Pesachim 19a
Food in which a needle which is Impure from Death is found, is impure; hands and the slaughtering knife aren't: Pesachim 19a-20a
Food in a vessel with a crawling creature becomes a Second Descendant Level of Impurity: Shabbat 138b, Pesachim 20a-b
Whether the stems of grapes being harvested for wine-making can receive impurity: Succah 13b
Whether the stems of vegetation being cut for the Roof of a Succah can receive impurity: Succah 13b
Stems of food, which are processed: Succah 14a
Annulling a thought which made the stems capable of receiving impurity, via another thought: Succah 13b-14a
Considering human flesh to be food: Keritot 21a-b
Making others impure
Food making its consumer impure rabbinically or biblically, vis-a-vis applying a lenient/stringent threshold quantity for communication of impurity: Yoma 80b
Ability of food to make other non-sanctified food impure rabbinically or biblically: Pesachim 14a, 18a, 18b-19a
Ability of terumah to make other food impure rabbinically or biblically: Pesachim 14a
Ability of korbanot to make other food impure rabbinically or biblically: Pesachim 14a
Ability of food to make Liquids impure: Pesachim 18b
Ability of food to make Vessels impure: Pesachim 18b, 19b
Status of a person who eats a half-shiur which has a higher level of impurity and then a half-shiur which has a lower level of impurity: Zevachim 31a
Odd Foods
Determining what constitutes "food" based on normal human behavior: Keritot 21a-b Fat, whether from korbanot or not, even from an animal corpse or tereifah [mortally wounded] animal, receives impurity of food: Pesachim 23a-b
Soft skins, unless worked for the time it takes to travel 4 Mil, get impurity like flesh does: Pesachim 46a
Wheat and barley found in animal feces: Menachot 69a
Soft, edible palm bark: Eruvin 28b
Unripe dates: Eruvin 28b
Animal hide: Eruvin 28b
An animal's placenta: Eruvin 28b
Human flesh: Keritot 21a
A dead bird of a kosher species, which is eaten in some places and not in others: Keritot 21a
