As I understand it, for something to count as a single act of eating, it must meet two requirements.
- The amount ingested must be the minimum of Kezayit. Some hold this to literally be the volume of a regular olive while others hold it to be the volume of an egg (~50cc).
- This amount must be consumed within 2 to 9 minutes (again, varying opinions).
My question is whether one earns the Karet punishment for eating chametz only while meeting these two requirements or is an even lesser amount still enough to earn Karet? For example, cooking in a not kosher for Pesach pot, or eating with not kosher for Pesach utensils and plates?