What is Issur Kolel in the context of "AIN ISSUR CHAL AL ISSUR" I heard two people talking about the concept please illustrarte with example and explain the illustration of the example?
Edit by YDK:
Example: A diseased animal (treifah) is forbidden to eat, even if properly slaughtered. If the slaughter is done improperly (nevela), this would normally create a 2nd issur when eaten. The rule of ain issur chal al issur would block the 2nd issur from setting since a previous issur exists with similar characteristics.
This block does not exist when the 2nd issur is "more forbidden" than the first. If the 2nd issur would be a mixture between the treifah and milk, the milk & meat issur would take effect since the 2nd issur also forbids benefit, whereas treifah did not (Issur mosif).